Cementitious foam compositions

ABSTRACT

Lightweight cementitious foams of the invention have excellent dynamic and dimensional stability due to use of foaming system comprising polycarboxylate surfactant foam generating agent, foam stabilizer (e.g., PVOH), and shrinkage reducing admixture to inhibit plastic shrinkage and micro-cracking of cement. The foaming system can be used in conventional cement mortars or concretes as well as with exemplary cementitious slurry systems of the invention, which include an expansive agent, a cross-linking agent for the foam stabilizer. Microfibers can be used in the foam, slurry, or both, to prevent micro-cracking. Cementitious foams can be made without use of autoclave or lightweight aggregates to achieve enhanced compressive strength and thermal insulation properties that compare favorably with conventional foams and insulation materials at comparable densities.

FIELD OF THE INVENTION

The present invention relates to light weight cement, and moreparticularly to cementitious foam slurries, methods for makingcementitious foam slurries, and cementitious foam materials and articlesmade from these.

BACKGROUND OF THE INVENTION

Foamed cementitious materials are desirable as building and constructionmaterials because of their light weight and conformability.

In U.S. Pat. No. 2,432,971, Ruthman et al. taught the use of a methylcellulose gel-like solution, activatible by heating, for preventingstructural collapse or migration of components in foams whoseconstituents were initially water-soluble or water-dispersible. Suchconstituents include foaming materials except those which render themethyl cellulose ineffective. Suitable foaming agents include saponincontaining materials, such as soap bark, soap weed, yucca root, puresaponin, etc. Foaming materials considered unsuitable include sodium andpotassium salts of fatty acids (see e.q., column 6, lines 1-17). Anumber of fiber materials can be mixed into the foam, includingcellulose fibers in the form of dried ground paper.

In U.S. Pat. No. 3,867,159, Dilnot disclosed the use of aqueousslurries, comprising finely ground calcareous and siliceous materials,and pre-soaked cellulose fibers to generate light weight materials. Thefoam is formed in advance of its mixture with the aqueous slurry, sothat the bubbles do not substantially coalesce or break down whensubsequently mixed into the slurry. Heating the foamed slurry byautoclave produces a rigid matrix having macroscopic spherical voids.

In U.S. Pat. No. 3,758,319 and U.S. Pat. No. 3,867,159, Ergene disclosedcellular structures made by admixing water and cement under conditionssufficient to produce a high degree of hydration of the cement, followedby introducing foam that has been formed under pressure using water,air, foaming agent (e.g., saponin, peptone, albumin, soap bark,water-soluble cellulose ester), and a chloride accelerator. The foammixture and cement mixture are blended to a substantially homogeneous,foamed cement slurry, which is cast into a mold and cured (e.g.,environmental steam or autoclave) to form a lightweight cellularconcrete structure.

In U.S. Pat. No. 3,963,507, Kuramoto et al. disclosed a porousconstruction material comprising a hydraulic material such as cement anda foaming agent comprising a water-soluble low-viscosity cellulose ether(e.g., 25-2000 centipoise), a water-soluble high-viscosity cellulosederivative (e.g., exceeding 2000 centipoise), and a PVOH foamingaccelerator which was at least 75%, and more preferably at least 85%,saponified.

In U.S. Pat. No. 3,989,534, Plunguian disclosed cementitious materialscomprising lightweight filler such as perlite, vermiculite, or hollowsilicate spheres in combination with a surface active foaming agent andwater-soluble organic film forming agents such as guar gum,pregelatinized starch, xanthan gum, and the like, which function as foamstabilizers. In U.S. Pat. No. 4,077,809, Plunguian explained a methodwherein the cement and light weight fillers and film forming agentscould be combined with pre-formed foams to create a foamed cementitiousmaterial useful for soundproofing and thermal insulation.

In U.S. Pat. No. 4,731,389, Christopher et al. (Aircrete) disclosedmethods for making foams suitable for insulating cavities andstructures. One example involved injecting air into an aqueous solutionof PVOH and a dispersant, and then adding the resultant foam to anaqueous solution or suspension of magnesium oxide and barium metaborateand a dispersant. An objective of the inventors was to provide afoam-cement mixture wherein the foam maintained sufficient integrity tomaintain its shape and volume until the inter-mixed cement hardened tofix the composition in place (col. 1, II. 37-42); and this wasaccomplished by mixing PVOH (polyvinyl alcohol) from the first componentwith barium metaborate in the second component to initiate and toaccelerate the setting of the foam, while providing integrity forsupporting the cement as it hardened in place (See col. 3, II. 37; Seealso col. 4, II. 12-20).

In U.S. Pat. No. 5,110,839, Chao disclosed a foamed compositioncomprising (a) about 100 parts by weight of a hydraulic substance suchas Portland cement, gypsum, or Plaster of Paris; and (b) about 25 toless than about 70 parts by weight water and about 0.01 to about 10parts by weight of a polymeric foam stabilizer having a weight averagemolecular weight of from about 1,000 to about 20,000 and comprising aC₁-C₁₂ alkyl carboxylic acid polymer. This composition could be formedby mixing a homogeneously foamed mixture of water and polymericstabilizer, and homogeneous slurry comprising cement and polymeric foamstabilizer.

In U.S. Pat. No. 5,641,584, Anderson et al. disclosed insulation barriermaterials having cement paste in combination with a rheology modifyingagent (e.g., methylhydroxyethylcellulose) and a lightweight aggregate(e.g., perlite, vermiculite, hollow glass spheres, etc.) to lower thedensity of the insulation barrier and increase its insulation ability. Apreferred method for making the insulation barrier materials includesthe steps of (1) mixing a powdered hydraulic cement and water to form acement paste; (2) combining a rheology-modifying agent(methylhydroxyethylcellulose) with cement paste such that the resultantcementitious mixture develops a more plastic rheology; (3) adding anaggregate material and/or entrained air to the cementitious mixture toimpart desired lightweight properties; (4) adding a fibrous material(such as abaca, glass, plastic, or metal fiber) preferably having a highaspect (length to width) ratio to the cementitious mixture in order toincrease toughness and strength; (5) molding the mixture into aninsulation barrier of a predetermined shape; and (6) allowing thecementitious mixture to harden into the predetermined shape. It wasdesired to obtain insulation barriers that were “form stable” in lessthan ten minutes.

In U.S. Pat. No. 6,547,871 and No. 6797054, Chatterji et al. disclosedfoamed well cement slurries which were comprised of hydraulic cement,sufficient water to form pumpable slurry, sufficient gas to generatefoam, and hydrolyzed keratin for stabilizing the foam within the slurry.

In U.S. Pat. No. 6,780,230 and World Patent App. No. WO 03/060018,Hilton et al. disclosed formulations and methods for spray-applyingcementitious fireproofing compositions onto a substrate. Pumpablecementitious slurry is formed and mixed with air, and then the slurry issubjected to mechanically created turbulence to generate gas bubbles andcreate a foam which is preferably stabilized by the presence ofpolyvinyl alcohol contained in the slurry. The slurry is pumped throughhoses to a nozzle for spray application. However, prior to dispensing, aset accelerator is injected into the foam slurry which causes the foamto gel, which in turn improves the hangability of the foam on thesubstrate.

Thus, various foamed cementitious systems are known in the art for avariety of applications and uses in the building and constructionindustries.

SUMMARY OF THE INVENTION

In surmounting the disadvantages of the prior art, the present inventionprovides dynamically and dimensionally stable cementitious foamslurries, methods for making cementitious foam slurries, as well ascementitious foam compositions, materials, and articles which are madefrom these methods and foam slurry compositions and which may be used asan alternative to foamed organic polymers, to cement compositescontaining lightweight aggregates, and to foamed gypsums.

As will be further described hereinafter, the present invention may beseen as a departure from, and patentable improvement over, U.S. Pat. No.4,731,389 (Aircrete) which described, as mentioned in the backgroundabove, adding a foam containing PVOH and dispersant to a cementcomponent containing magnesium oxide and barium metaborate to initiatesetting.

Advantages of the present invention over the prior art include enhanceddynamic stability of the cementitious foam. In other words, a greaterdegree of uniformity and bubble spacing is achieved while the materialis in a pre-hardened yet hardening plastic state, and this enhances, inturn, the dimensional stability of the cementitious foam resulting fromthe cementitious foam slurry. The enhanced dynamic and dimensionalstability is particularly significant when foam density is 0.1 g/cm³ orless.

The present invention achieves dynamic stability without the need forincorporating light weight aggregates due to its dependable, fine, andclosed-cell morphology as generated within the foam slurry. Compared toprior art foamed cements at similar densities, cementitious foams of thepresent invention have significantly lower thermal conductivity, highercompressive strength, and greater resistance to degradation from theeffects of water.

Dimensional stability is enhanced by modifying the foam stabilizer(e.g., polyvinyl alcohol or “PVOH”) such that it is can operate athigher air content. The present inventors realized that the time duringwhich the foam is stable is limited due to cross-linking of the foamstabilizer (PVOH) and due to shrinkage of cementitious foam duringhydration and water evaporation. Although a conventional viscositymodifying agent (VMA), such as methylcellulose, can work somewhat toimprove foam stability (see e.g., U.S. Pat. No. 2,432,971, U.S. Pat. No.4,077,809), the present inventors believe that prior art approaches(e.g., Aircrete patent) fall short because they do not sufficientlyfocus on providing favorable dynamic conditions by which fineclosed-cell bubble structures can be generated during a plastic stateand captured in a hardened state without cracking.

An exemplary composition of the invention for making a cross-linkedfoamed cementitious product comprises: a polycarboxylate surfactant forgenerating foam (which may be referred to hereinafter “PC”), a foamstabilizer, and a shrinkage reducing admixture (or “SRA”) operative toreduce plastic shrinkage in a hydrating cementitious composition. Thefoam-generating composition preferably further includes a calcium salt(preferably non-chloride), a viscosity modifying agent (“VMA”), aplurality of microfibers, an optional fatty acid water repellent, ormixtures thereof, or all of these optional components.

An exemplary method of the invention comprises combining the abovedescribed composition with hydratable cementitious slurry to generatecementitious foam slurry, which would then cure into a hardenedcementitious foam material or structure. An exemplary cementitiousslurry composition of the invention comprises a hydratable bindercomprising Portland cement (which could optionally further comprisesecondary cementitious materials such as fly ash, granulated blastfurnace slag, limestone, pozzolans, etc.), an expansion agent forexpanding by chemical reaction the volume of a cementitious slurry(preferably selected from the group consisting of calcium oxide,magnesium oxide, and calcium sulfoaluminate); and a cross-linking agentfor the foam stabilizer (e.g., a borate compound).

Hence, the present invention may also be comprehended in terms of a foamgeneration system (hereinafter “foam component” or “foam system”) andcementitious slurry generation system (hereinafter “slurry component” or“slurry system”), which together provide a cementitious foam slurry thatcures or hardens into a hardened mass or three-dimensional structure(e.g., an article such as a board, brick, block, paver, beam, panel,door, window or door frame, column, fence post, or the like).

Thus, in exemplary cementitious foam slurries, foam materials, foamstructures (articles), and methods of the present invention, thefollowing components are employed: (i) a PC surfactant for generatingfoam; (ii) a foam stabilizer (e.g., PVOH, PVA); (iii) a shrinkagereducing admixture; (iv) a calcium salt in the amount of 0%-2.1% byweight of solids based on total weight (the calcium salt beingpreferably selected from the group consisting of calcium nitrite,calcium nitrate, or a mixture thereof); (v) a viscosity modifying agent;(vi) a hydratable binder comprising Portland cement; (vii) an expansionagent for expanding by chemical reaction the volume of cementitiousslurry (the expansion agent being preferably selected from the groupconsisting of calcium oxide, magnesium oxide, and calciumsulfoaluminate); (viii) a cross-linking agent for the foam stabilizer(preferably selected from the group consisting of a borate, sulfate,gluconate, and mixtures thereof); and (ix) a plurality of microfibersoperative to reduce plastic shrinkage cracking of the Portland cementwhen it is mixed with water in an amount to initiate hydration.

In preferred embodiments, an expansive agent is used for chemicallyexpanding the volume of the cementitious slurry; while the shrinkagereducing admixture (SRA) is employed to reduce drying shrinkage as wellas some plastic shrinkage of the cementitious slurry, and microfibersare employed to provide mechanical restraint to plastic and dryingshrinkage of the cementitious slurry.

Although it may be possible to omit the use of a calcium salt if thefoam is being generated in a static mixer, it is desirable to employ acalcium salt, such as calcium nitrite, to slow cross-linking of the foamstabilizer (e.g., PVOH). The cross-linking of the foam stabilizerotherwise creates further unwanted shrinkage, and also offsets theretardation of cement component due to borate cross-linking agent. Thecalcium salt moreover acts to accelerate the setting of cement, and thiscan offset the retarding effect of borates used for cross-linking thefoam stabilizer (PVOH).

In exemplary cementitious foam slurry compositions and methods of theinvention, the foam system can include the calcium salt (calciumnitrite), while the cementitious slurry system can include a boratecross-linking agent for the foam stabilizer (e.g., sodium metaborate).These dynamic characteristics mentioned above would be particularlyadvantageous where the foam and slurry components are separatelypackaged and separately mixed with water to create separate foam andslurry systems. For example, calcium nitrite would act to slowcross-linking of the PVOH foam stabilizer when water is added togenerate the foam; and the borate compound would retard the setting thecement when water is added to generate the slurry; and then, after thefoam and slurry are formed separately and then mixed together, thecalcium would act to accelerate the cement while the borate would act tocross-link the borate.

Microfibers may be used in the foam system, cementitious slurry system,or in both systems to enhance the ability of the foam and/or slurry toresist segregation of components and to prevent micro-cracking duringshrinkage, particularly at low densities. Exemplary microfibers have aneffective diameter of 5-50 microns, and are made of cellulose or, morepreferably, a synthetic polymer (e.g., polyolefin). Preferredmicrofibers are made of polyethylene, polypropylene, or blends andmixtures thereof, and are coated with a shrinkage reducing admixture(SRA) or agent to enhance bond strength in cement (See e.g., U.S. Pat.No. 5,399,195).

The exemplary cementitious foams of the invention may be made bycombining water with a unitary mixture containing both the foam systemcomponents and slurry system components. More preferably, thecementitious foams are made by separately making the foam and slurry andthen combining the separately generated foam and slurry systemstogether.

The foam and slurry components may be packaged separately for thispurpose. As an example, components (i) through (v) can comprise the foampackage, while components (vi) through (viii) can comprise the slurrypackage. The microfiber component (ix) may be incorporated in either orboth packages. In other exemplary embodiments, the calcium saltcomponent (iv) can be included in the slurry rather than foam system. Instill further exemplary embodiments, it is possible to package the PCsurfactant component (i) in both of the foam and slurry packages.Similarly, the SRA component can be packaged as part of either or bothof the foam and slurry packages.

An exemplary method of the invention comprises mixing components (i)through (ix) with water to generate cementitious foam slurry, which thenhardens into a mass or is shaped into a hardened article or structure.Exemplary methods include molding the cementitious foam slurry intostructures (e.g., boards, panels, beams, bricks, blocks, etc.);injecting it into cavities (e.g., cavities in walls or ceilings); andspray-applying it against surfaces and substrates (e.g., in the natureof spray-applied fireproofing or insulation against building structures,beams, panels, etc.). The methods of the invention do not requireautoclaving or the use of metallic additives that generateinterconnected air voids.

The present invention also provides cementitious foams as well asarticles and structures made from the aforementioned cementitious foamslurries and methods. In still further embodiments, one or more optionalcomponents may be incorporated in either or both of the foam and slurrysystems, including, without limitation, air entraining agents, airdetraining agents, hydrophobic agents (e.g., fatty acids), fillerparticles (e.g., fine particulates of cement, limestone, silica fume,pozzolans, inert fillers), and structural reinforcing fibers (i.e.,“macrofibers”).

Various aggregates may be optionally added, including light weightaggregates (e.g., polystyrene beads), as well as conventionalaggregates, such as sand to make a lightweight mortar and crushed gravelto make a lightweight concrete. Cementitious foam slurries of thepresent invention may be incorporated into conventional mortars andcements to lower the density using a highly stabilized air structure.

In addition to cementitious foam compositions, and to components andmethods for making the same, the present invention also providesarticles made from the cementitious foam and foam slurry compositions ofthe invention. Exemplary articles include sheet substrates, such as:wallboards to replace (e.g., to substitute for) gypsum-based dry wall;roof decking to replace oriented strand board; and panels to replacepolyurethane foam insulation.

In further embodiments, cementitious foams of the invention may be soldas part of laminated, coated, or injected assemblies—such aspre-waterproofed exterior wall boards or roof decking havingpre-attached or pre-adhered waterproofing membrane, vinyl-cladclapboards for house exteriors, or as foam core in steel doors—becausegaps and discontinuities at the interface between the cementitious foamand other materials are minimized.

Further advantages, features, exemplary embodiments, and exemplaryapplications of the invention are described in further detailhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

An appreciation of the benefits and features of the present inventionmay be more readily apprehended by considering the following writtendescription of exemplary embodiments in conjunction with the drawings,wherein

FIG. 1 is a photograph of ten different air-dried cementitious foamsamples described in Example 1 wherein samples P1-P9 demonstrated gapsat form walls, cracking, and/or overall reductions in volume, and sampleP10 demonstrated excellent dimensional stability;

FIG. 2 is a set of side-by-side comparative photographs of air driedcementitious foam sample P10 (left photo) and sample that did notcontain SRA or fibers (right photo);

FIG. 3 is a set of side-by-side comparative photographs of air driedcementitious foam sample P10 (left photo) and sample that did notcontain calcium nitrite (right photo);

FIG. 4 is a graph plot of density (horizontal axis) against K-value(vertical axis) based on published insulation performance values forcommercially available inorganic insulation materials which includedlightweight cement-based insulation; a “light weight” concrete; a gypsumboard; and a lightweight insulating concrete;

FIG. 5 is a graph plot of density (horizontal axis) against airpermeability (vertical axis) of commercially available insulation,plywood sheeting, and gypsum board;

FIG. 6 is a set of microphotographs of an exemplary light weightcementitious foam composition of the present invention, wherein theright photo shows closed cell bubbles that are less than one mm (asindicated by the markings which are spaced 1 mm apart), and wherein theleft photo is a higher magnification of the closed cell bubbles whereinthe matrix of bubbles are seen to be highly distinct, with minimalmaterial between the closed pores;

FIG. 7 is a graphic plot of density (horizontal axis) against vaporpermeance (vertical axis) of commercially available insulation board,gypsum board, and expanded polystyrene;

FIG. 8 is a set of photographs of a sample of cementitious foam P37 ofthe present invention (left photo) and the use of this material in acorrugated steel deck (right photo);

FIG. 9 is a set of photographs of exemplary laminates of the inventionwherein, as shown in the left photo, a sample cementitious foam P35 wascast against an aluminum foil, and, as shown in the right photo, thealuminum did not corrode due to the presence of calcium nitrite;

FIG. 10 is a set of four photographs, the lower left photo depicting a(PRIOR ART) commercial gypsum dry wall product (commercially availableunder the trade name Dens Glass Gold®) fastened against a frame usingstandard fasteners, the upper left and lower right photos depictingexemplary cementitious foam boards P35 of the present invention whichwas fastened to a steel stud wall using screws, and the upper rightphoto depicting an exemplary cementitious foam sample P36 of the presentinvention that was poured to fill a steel stud;

FIG. 11 is a graph plot of the density (horizontal axis) againstcompressive strength (vertical axis) of commercial (PRIOR ART) gypsumboard materials;

FIG. 12 is a graph plot, in terms of time (horizontal axis) againstshrinkage measured in terms of length-wise shrinkage (vertical axis) ofa cement samples containing various glycols, including hexylene glycol(HG), one of the preferred SRAs in the present invention, and alsoincluding (PRIOR ART) glycols including 1,3 butylene glycol, andINDOPOL™ L-14, compared to a control sample;

FIG. 13 is graph plot of deflection (horizontal axis) against stress(vertical axis) of cement samples containing fibers compared to controlsample; and

FIG. 14 is a graph plot of displacement (horizontal axis) against stress(vertical axis) of a commercially available gypsum wall board (DensGlass Gold) compared to cementitious foam compositions of the presentinvention which incorporated macrofibers (STRUX®) or mesh.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

All parts and percentages of components described herein are by weightunless otherwise indicated. The term “S/S” means weight of solidadditive based on weight of the hydraulic cement.

Reference to a salt or acid will be understood to refer to and toinclude the corresponding acid or salt unless otherwise indicated orcontextually impermissible. Those of ordinary skill in the art willrealize that references herein to a salt (e.g., polycarboxylate, borate)includes the corresponding acid (polycarboxylic acid, boric acid), andvice versa; as it may be possible for both salt and acid forms toco-exist or for one of these forms to predominate to exclusion of theother, depending on conditions.

The term “Portland cement” as used herein means the general compositionas generally described in the Background section. This term includeshydratable cement which is produced by pulverizing clinker consisting ofhydraulic calcium silicates and one or more forms of calcium sulfate(gypsum) as an interground additive.

The term “cementitious” as used herein refers to materials that comprisePortland cement or which otherwise function as a binder to hold togetherfine aggregates (e.g., sand), coarse aggregates (e.g., crushed gravel),or mixtures thereof. Such cementitious materials may further include flyash, granulated blast furnace slag, lime stone, silica fume, or otherpozzolans or pozzolanic material which may be combined with Portlandcement or be used to replace or substitute for a portion of the Portlandcement without serious diminishment of hydratable properties.

The term “hydratable” as used herein is intended to refer to cement orcementitious materials that are hardened by chemical interaction withwater. Portland cement clinker is a partially fused mass primarilycomposed of hydratable calcium silicates. The calcium silicates areessentially a mixture of tricalcium silicate (3CaO.SiO2) and dicalciumsilicate (2CaO.SiO2) in which the former is the dominant form. See e.q.,Dodson, Vance H., Concrete Admixtures (Van Nostrand Reinhold, New YorkN.Y. 1990), page 1.

The term “slurry” is often used herein to refer to a cementitiousslurry, or paste, which is formed by mixing together the cementitiousmaterial (e.g., Portland cement or other cementitious material alone, ora mixture of Portland cement and one or more other cementitiousmaterials) with water to initiate the hydration (or curing) reactionwhich results in a hardened cementitious mass or structure. The terms“structure” and “article” may be used interchangeably herein.

The term “mortar” as used herein will typically refer to a cement,cementitious mixture, or cementitious slurry having a fine aggregate,such as sand, while the term “concrete” will refer to a mortar furthercomprising a coarse aggregate, such as crushed stones or gravel. Hence,it will be understood that the present invention will also providecementitious foam mortars and concretes by combining the cementitiousfoam slurry with conventional mortars and concretes. Exemplarylightweight mortars and concretes can also be achieved by optionallyincorporating lightweight aggregates (e.g., polystyrene beads) withcementitious foam slurries made in accordance with the presentinvention.

As previously summarized, exemplary cementitious foam compositions ofthe invention, comprise: (i) a polycarboxylate surfactant; (ii) a foamstabilizer; (iii) a shrinkage reducing admixture. Preferred foam andfoam-generating systems may further comprise a (iv) calcium salt(preferably non-chloride), (v) a viscosity modifying agent, a pluralityof microfibers, a fatty acid water repellent, or mixtures thereof, orall of these optional components.

The exemplary foam composition can be introduced, either in dry powderor wet (foamed) form, into conventional mortars and concretes togenerate light weight structures and articles (products), and, morepreferably, are combined with cementitious slurry-generating componentsystems of the invention, which comprise an expansive agent and a boratecompound.

Thus, an exemplary “cementitious foam slurry” (when wet) or“cementitious foam” (when dry) of the present invention comprises: (i)polycarboxylate surfactant for generating foam; (ii) a foam stabilizer;(iii) a shrinkage reducing admixture operative to reduce plasticshrinkage in a hydrating cementitious composition; (iv) a calcium saltin the amount of 0-2.1% based on total weight; (v) a viscosity modifyingagent; (vi) a hydratable binder comprising Portland cement; (vii) anexpansion agent for expanding by chemical reaction the volume of acementitious slurry; (viii) a cross-linking agent for the foamstabilizer; and (ix) a plurality of microfibers operative to reduceplastic shrinkage cracking of the Portland cement when it is mixed withwater in an amount to initiate hydration of the cement.

The components of the exemplary cementitious foam composition of theinvention may be in dry powder form. For example, components (i) through(ix) may be packaged as a unitary mixture to which water can beincorporated and mixed to generate cementitious foam slurry.

Alternatively, components (i) through (v) may be packaged separately asa foam-generating component system “A”, and components (vi) through(viii) may be packaged separately as a slurry-generating component “B”,with the plurality of microfibers being packaged with either component Aor B, or with both of them.

In further exemplary embodiments, it is similarly possible to packagethe calcium salt (e.g., calcium nitrite) in either or both of the foamand slurry systems.

Additionally, the PC surfactant foam generating component can beincluded in the cementitious slurry system as well as in the foamsystem.

Whether packaged in separate containers or in a single container, thedry formulation can be combined with water, at the factory or at theapplication site, to generate hydratable cementitious foam that can bemolded into shape prior to setting and hardening into final shape. Forexample, the separate foam and slurry components can be mixed with waterseparately and are stable for at least 15 minutes and when combinedprovide at least 5 minutes of working time for pouring into a form(mold) or cavity or pumping for injection into a mold or for sprayapplication against a surface or substrate. Alternatively, all thematerials can be mixed together with water and then the foam volumeenhanced by using a high shear mixer (such as Hobart with large bladefor entraining air into the mix), a static mixer (wherein air and liquidare sent through a porous medium or tortuous path to produce foam), orthrough an air injected hose and nozzle as disclosed in U.S. Pat. No.6,780,230 B2. In case of spray application or injection, however, it maybe preferable to add the borate last, such as near the injector or hosenozzle.

The relative percentage amounts of the afore-mentioned components willdepend greatly upon the desired density of the final cementitious foamproduct or structure to be made. For example, lower density cementitiousfoams will likely have a smaller percentage of the cementitious slurrycomponents, while higher relative density cementitious foams will have agreater percentage of the cementitious slurry components.

Exemplary percentage ranges for the afore-mentioned components areprovided as set forth below. All percentages reflect solids ofcomponents based on total weight of these components and water intowhich the components are mixed for making the final cementitious foamslurry.

(i) polycarboxylate surfactant 0.1-1.5% (ii) foam stabilizer 1.5-6.0%(iii) shrinkage reducing admixture 1.0-3.5% (iv) calcium salt 0.0-2.1%(v) viscosity modifying agent 0.01-0.2% (vi) hydratable binder21.0-40.0% (vii) expansion agent 5.0-12.5% (viii) cross-linking agentfor foam stabilizer 0.05-1.0% (ix) microfibers 0.1-1.7%

Note that the above percentages do not add up to 100% (because waterwould be used to make up the remainder). The lower percentage in theranges suggested above may even be lower in case certain optionalcomponents are incorporated into the foam and/or slurry systems, such aslightweight aggregates (e.g., perlite, polystyrene beads, shreddedexpanded polystyrene), sand, crushed stones or gravels, particlefillers, etc.). The afore-mentioned components (i) through (ix) of thecementitious foam compositions of the invention are further described indetail in the paragraphs which follow.

(i) Polycarboxylate Surfactant.

Exemplary polycarboxylate surfactants suitable for use in the inventioninclude conventional polycarboxylic acid or salt type cementdispersants, especially those which do not contain added defoamingagents and which do not have excessive superplasticizing capabilities.

A preferred polycarboxylate surfactant which is particularly suitablefor use in the present invention, because it has high entrainingcapacity, is commercially available from Rohm & Haas (now part of DowChemical) under the trade name TAMOL™. For example, the product TAMOL™731A (the “A” designates that this product is dissolved in solution,while “DP” designates a dry powder which can be re-dissolved in anaqueous solution) is a copolymer of maleic acid and diisobutylene. Thus,preferred PC surfactants include diisobutylene-maleic acid copolymersand the sodium or ammonium salts thereof. TAMOL™ 731A is provided as thesodium salt of the acid, having pH of about 10, and solids of 25% withwater as diluent. Molecular weight is approximately 10,000 Daltons.

(ii) Foam Stabilizer.

Exemplary foam stabilizers are selected from the group consisting ofpolyvinyl alcohol (PVOH), polyvinyl acetate (PVA), or mixture thereof.PVOH having various degrees of hydrolysis may be used. As demonstratedlater in one of the examples, it was discovered that costs can belowered for low density foams by lowering the PVOH content bysubstituting added amounts of methyl cellulose for portions of the PVOH(See Example 20).

(iii) Shrinkage Reducing Admixture.

Exemplary shrinkage reducing admixtures (“SRAs”) suitable for use in thepresent invention include known SRAs, as disclosed in U.S. Pat. Nos.5,556,460, 5,618,344, 5,779,788, 5,603,760, 5,622,558, 6,277,191, andothers. Preferred SRAs are those which are not strongly defoaming.

For example, a preferred SRA is an alkylene glycol represented by thegeneral formula HOBOH wherein B represents a C₃-C₁₂ alkylene group,preferably a C₅-C₈ alkylene group. Examples of such glycols are 1,6hexanediol, 1,5-pentanediol, 1,4-pentanediol, 2-methyl-2,4-pentanediol,and the like.

As another example, an exemplary SRA may be a diol such as a secondaryand/or tertiary dihydroxy C₅-C₈ alkane represented by the formula:

wherein each R independently represents a hydrogen atom or a C₁-C₂ alkylgroup, each R′ represents a C₁-C₂ alkyl group and n represents aninteger or 1 or 2.

Of the diol-based SRAs, the most preferred is 2-methyl-2,4-pentanediol,which is sometimes referred to as “hexylene glycol” (“HG”).

Generally, the preferred glycols would not include butyl ethers. Forexample, alkylene glycols believed to be useful for the presentinvention can include condensed alkylene glycols represented by theformula HO(AO)_(X)H wherein A represents a propylene and more preferablyan ethylene or methylene; 0 represents an oxygen atom and x is aninteger of from 1 to about 20, preferably from 1 to 10, provided thediol is soluble in water. The AO group in a particular glycol moleculemay all be the same or different. Examples of such glycols includediethylene glycol, dipropylene glycol, tripropylene glycol,di(oxyethylene)di(oxypropylene) glycol as well as poly(oxyalkylene)glycols. The AO groups of such polyoxyalkylene glycols may be of singlealkylene or a mixture of alkylene groups which are in either block orrandom configuration.

(iv) Calcium Salt.

The use of calcium salts in the either the foam or cementitious slurrysystem is preferred in most cases, unless the cementitious foam is beinggenerated in a static mixer. Calcium chloride can be used, butnon-chloride salts are preferred due to the corrosion damage caused bychloride to metals. Thus, a preferred calcium salt is calcium nitrite,calcium nitrate, or a mixture thereof. The calcium salt is believed toslow the cross-linking of the foam stabilizer (e.g., PVOH) while actingalso as a set accelerator for the hydratable cementitious binder (e.g.,Portland cement). The use of calcium nitrite is preferred. Calciumnitrate may be used in combination with the calcium nitrite in up to a50:50 weight ratio.

(v) Viscosity Modifying Agent (VMA).

Exemplary VMAs believed to be suitable for purposes of the presentinvention can be selected from the group consisting of: (a) biopolymerpolysaccharides including S-657 (diutan), welan gum, xanthan, rhamsan,gellan, dextran, pullulan, and curdlan; (b) marine gums such as algin,agar, and carrageenan; (c) plant exudates such as locust bean, gumarabic, gum Karaya, tragacanth, and Ghatti; (d) seed gums such as guar,locust bean, okra, psyllium, and mesquite; and (e) associativethickeners such a cellulose (or modified cellulose), hydrophobicallymodified alkali swellable acrylic copolymer, a hydrophobically modifiedurethane copolymer, polyurethane thickeners, polyacrylates, polyethers;and derivatives and mixtures of any of the foregoing.

Preferred VMAs include methyl cellulose, hydroxylethyl cellulose, methylhydroxyl cellulose, hydroxylmethyl ethyl cellulose, carboxy methylcellulose, methyl cellulose, ethyl cellulose, hydroxylethyl cellulose,hydroxyl ethyl propyl cellulose, and the like.

The present inventors believe that alkali soluble emulsions (“ASE”),e.g., comprising acrylic acid and/or methacrylic acid monomers, mayprovide interesting benefits in terms of maintaining dynamic stabilityof the cementitious foam system. At low pH, the emulsion has lowviscosity, but at higher pH the polymer dissolves and increasesviscosity of the system. Similar VMA materials include hydrophobicallymodified alkalie soluble emulsion (“HASE”), hydrophobically modifiedethylene oxide urethane (“HEUR”), and hydrophobically modifiedhydroxylethyl cellulose (“HM-HEC”). If such VMA materials were employed,they could be incorporated into a separate foam component, which thencould be added to cement component to generate cementitious foam slurry.

(vi) Hydratable Cement(itious) Binder.

Cementious foams and slurries of the invention comprise Portland cement,which may be optionally combined with other cementitious materials, suchas one or more of fly ash, granulated blast furnace slag, densifiedsilica fume, limestone, and other pozzolans or pozzolanic materials.

In exemplary embodiments of the invention, hydrated cement particles canbe used to deliver one or more of the various foam or cementitiousslurry components as taught in U.S. Pat. No. 6,648,962 B2 of Berke etal. Thus, one may hydrate cement with calcium nitrite, crush the driedparties, and then coat the crushed particles with SRA (e.g., HG) and afatty acid (oleic and stearic acid or salt).

If the cementitious slurry component is packaged or prepared separatelyfrom the foam generation component, it is preferred for the cementitiousslurry component to contain a polycarboxylate surfactant that isidentical to or different from the polycarboxylate surfactant used inthe foam generation component (see above).

(vii) Expansion Agent.

An exemplary expansion agent suitable for use in the invention isselected from calcium oxide, magnesium oxide, calcium sulfoaluminate(“CSA”), or mixtures thereof. The latter is most preferred.

(viii) Cross-Linking Agent for Foam Stabilizer.

Exemplary agents for cross-linking the foam stabilizer (e.g., PVOH)include borates, sulfates, aluminates, and the like. Barium borate,sodium borate, and sodium tetraborate are preferred. Barium borate ispreferred when the foam and slurry components are combined as apre-mixed material. Sodium borate or tetraborate are preferred wherecombination with foam stabilizer is of short duration after they aremixed (e.g., such as in spray applications wherein the components andmixed and then sprayed in relatively quick succession).

(ix) Microfibers.

Preferably, the microfibers are contained in at least the cementitiousslurry component, and may be used in volume fractions up to 1% based onPortland cement fraction without adversely affecting workability.

Exemplary microfibers of the present invention have an average effectivediameter (or mean transverse dimension) of 5-50 microns, and morepreferably 10-25 microns for fibers under 2 mm long, and 25 to 50microns for fibers 2 to 8 mm long. The fibers may comprise cellulose orsynthetic polymer (e.g., polyolefin), or even be made of glass.

Exemplary microfibers suitable for use in the present invention aredisclosed in U.S. Pat. No. 5,399,195 of Hansen et al. These microfiberscomprise a polyolefin, a polyolefin derivative, a polyester, or mixturethereof, and have an average length of 1-30 mm, a mean transversedimension of 5-30 um, and an aspect ratio of 100 to 1000.

Most preferred microfibers for use in the present invention include thecoated fibers taught by Neal Berke et al. in U.S. Pat. No. 5,753,368.These fibers are coated by a type of material operative to reduceplastic shrinkage of cement. For example, Berke et al. disclosed inExample 2 the use of polypropylene fibers having a length of about twoinches (about 5 cm) and a diameter of 0.0255×0.0395 inches, which werecoated with di-propylene glycol-t-butyl ether (“DPTB”) for enhancedconcrete bonding strength and improved pull-out resistance. Berke et al.taught the use of polypropylene fibers coated with a material selectedfrom particular glycol ethers (such as DPTB), having at least threecarbon atoms in an oxyalkylene group, and glycerol ethers (such asdi-t-butyl glycerol).

Preferred microfibers suitable for use in the present invention arecomprised of polypropylene and having sufficiently small dimensionsoperative to inhibit self-induced, or so-called plastic shrinkage, andpreferably having a coating operative to decrease air entrainment at thepaste-fiber interface, thereby enhancing wetting between hydrophobicfiber material and the hydrophilic matrix of the cement, resulting inincreased bond strength between the fiber and cement paste. The coatingmaterial may comprise DPTB or other known SRAs (e.g., hexylene glycol),as described elsewhere in this specification, or as otherwise known inthe concrete industry.

Microfibers may be packaged with the other components (i)-(viii) in aunitary mixture, or, where separate foam-generating andslurry-generating system components are separately packaged, preferablywith both of the system components and at least with the cementitiousslurry-generating component system.

Optional Macrofibers (Reinforcing Fibers).

In further exemplary embodiments, longer and larger fibers mayoptionally be incorporated into the cementitious foam to enhance itsmechanical properties.

For example, a polypropylene reinforcing fiber, having a flat noodleshape, is commercially available from Grace Construction Products,Cambridge, Mass. USA, under the trade name “STRUX®.” The advantage ofusing these fibers over glass fibers is their lower density, and theiradvantage over cellulose is their enhanced workability and chemicalresistance. The amount of such fibers used can be up to one or even twopercent by weight based on the total weight of the cementitious foamslurry composition in accordance with the invention.

Commercially available structural reinforcing fibers that may notpossess the same modulus of elasticity and/or individual load carryingcapability of the STRUX® brand fibers are also suitable for use in thepresent invention, since the overall strength of the foam matrixes ismuch lower than that of normal weight concrete.

Generally, the dimensions of suitable structural reinforcing fibers,which may be referred to as “macrofibers” in contrast to theabove-described microfibers, and such macrofibers have an average width(or equivalent diameter) of 1.0-5.0 mm, an average thickness (wherequadrilaterial in cross-section) of 0.05-0.2 mm, and average individualfiber length of 20-75 mm.

Other Optional Additives, Particles, and Fillers.

In further embodiments, one or more conventional concrete additives,admixtures, and fillers may be incorporated and used where specificbenefits are desired.

For example, conventional fatty acids or their salts may be incorporatedto the foam system to achieve water repellency. Fatty acids should notwork to defoam the cementitious slurry, and thus non-defoaming fattyacids should be used. Examples include oleic acid and stearic acid. Acalcium stearate suspension, provided in the form of finely groundcalcium stearate powder, dispersed in an aqueous carrier, iscommercially available from Grace under the tradename DARAPEL®. Thefatty acids should not be air detraining (e.g., containing butyl groupssuch as butyl stearate or butyl oleate). Mixtures containing variousfatty acids are commercially available and may be used so long as theydo not defoam or otherwise detrain substantial amounts of air from thecementitious foams and slurries.

Fine particles may also be added into foam and/or slurry system. Forexample, crushed limestone, silica fume, mica, wollastonite,vermiculite, and talc may be added to the foam as mini-shear enhancers.Such fine particles should be inert in water, and may permit the airvolume to be controlled in more predictable fashion in some cases. Theparticles can be advantageously mixed in with either or both of the foamand slurry components, such as with the microfibers. Silica fume can beused preferably in separate foaming packages.

Other fillers can be used to make mortars and concretes. Exemplarycementitious foams and foam slurries of the invention may furtherinclude sand (as a fine aggregate) to make light weight mortars, andcoarse aggregates such as crushed stone or concrete to make a lightweight concrete. Fillers such as bauxite and other clays can be used toincrease density.

There are a number of exemplary methods of the invention for generatingthe cementitious foam compositions, materials, and articles of theinvention.

One such method is to add the foam components into a high shear mixeruntil the specific gravity is approximately 0.05. The cementitiousslurry components may be mixed separately at the same time, but does notrequire high shear mixing. The separate foam and slurry components arethen mixed into each other, and macrofibers (e.g., STRUX® reinforcingfibers) are added at this time if desired. The cementitious foam slurryis then either pumped, poured, or pumped to spray application. Ifsprayed or pumped, borate or additional borate and/or carbonate sourcecan be added at the end of the spray or pump to accelerate hardening bycross-linking and reacting the cement.

A second exemplary method, which is similar to the first, is to mix allcomponents together with water at moderate shear and then pump the mixedcomponents through a hose using air pressure, similar to what wasdisclosed in U.S. Pat. No. 6,780,230 B2. Alternatively, the separatefoam and separate cementitious slurry components can be mixed separatelyas in the first method, but without the high sheer mixing, and added intwo streams to the air pressurized spray hose.

A third exemplary method is to add all materials together in a highshear mixer to produce the cementitious foam slurry. The foam slurry canthen be pumped, poured, sprayed, or trowelled into place, into a form ormold or cavity, or otherwise against a surface or substrate. Thematerials can be combination of dry and wet components to which water isadded, or they can be provided in dry form to which water is added.

A particularly advantageous feature of the present invention is that thedensity of the cementitious foam can be controlled by adjusting thecement content and/or the addition of optional aggregates. The foamformulations with the addition of fine particles produce a uniformvolume of foam under high shear mixing. If the fine particles are notadded, then the foam will increase in volume upon mixing with thecementitious slurry; and increasing the amount of the slurry does notincrease density as much as calculated from the volume of slurry added.If the foam portion has fine particles, then the increase in density iscloser to what would be calculated. This allows for standard foamcompositions that can be used to make materials from 0.05 to greaterthan 1.0 Sp.G (Specific Gravity).

In further exemplary compositions and methods of the invention, thecementitious foam slurries, and the cementitious foam masses or articleswhich are hardened into form from such slurries, may further compriseone or more of the following conventional additives or fillers: (a) alightweight aggregate selected from the group consisting of vermiculite,expanded polystyrene, perlite, and mixtures thereof; (b) a macrofiber(e.g., structural reinforcing fiber, which can be made from polyolefinsuch as polyethylene, polypropylene, or blend thereof); (c) a waterrepellant agent; (d) particles of cement, supplemental cementitiousmaterial, or filler having an average particle size of no greater than 1mm; (e) fine aggregate (e.g., sand); (f) coarse aggregate (e.g., crushedstone or gravel having average particle size of 0.5-2.0 cm); or (g)mixture of any of the foregoing.

Cementitious foam materials of the invention can be made air-impermeableby increasing specific gravity (Sp.G) to about 0.2. At a higher Sp.G,such material has a higher R value and lower K value compared to otherlightweight cementitious materials.

The cementitious foams of the invention, as previously mentioned, can beused to produce boards and other shapes that can be reinforced withmesh, membranes (e.g., plastic sheeting, pre-formed waterproofingadhesives), or aluminum backing. The present inventors believe thatother thin metals would work also. The use of mesh on one side of aboard or other article shape can facilitate drying of the cementitiousfoam material cast or formed against it. A mesh can be made of plastic,steel, aluminum, fiberglass, or other material.

Cementitious foam slurries of the invention may cast against sheetmaterials to provide enhanced waterproofing and barrier protection,along with structural mechanical enforcement. The sheet can be awaterproofing membrane such as commercially available from GraceConstruction Products under the trade names PREPRUFE®, FLORPRUF®, ICE &WATER SHIELD®, PERMA-BARRIER®, VYCOR®, and TRI-FLEX®. The waterproofingmembrane can have a pre-formed adhesive layer operative to adhere apolymeric support layer to the cementitious foam. In the case of thePREPRUFE® membrane (which is designed particularly for “blind-side”applications where fresh mortar or concrete may be cast against theadhesive side), it is particularly appropriate to cast the cementitiousslurry foam against the adhesive and allow it to cure against themembrane. The sheet can also be aluminum foil for added reflectivity andimpermeability. One of the advantageous features of the cementitiousfoam slurries of the present invention is that calcium nitrite willprotect the aluminum from alkaline attack from the cement.

Board articles can be manufactured, and depending on their density canbe used for fire protection, thermal insulation, or combination of theseproperties. These boards can be used as replacements or substitutes forgypsum board, DENS GLAS GOLD® boards, sheetrock, plywood, and the like,with lower weight per board foot and higher R values (at similardensities), for either interior or exterior application. The boards workwell with dry wall fasteners and can be nailed.

Moreover, such boards or other articles made from the cementitious foamsof the invention can be dried at room temperature or elevatedtemperatures without requiring autoclaving. For example, a temperatureof 60 degrees Celsius is sufficient for this purpose.

The materials of the invention can be poured or pumped onto roofs as aninsulating barrier which provides up to, or even more than, twice the Rvalue obtained from commercially available (prior art) cementitiousmaterials.

Indeed, the cementitious foam slurries of the invention can be poured orinjected into shaped molds and hardened to assume the shape of the moldor form, which can be removed or which can become integrally attached,bonded, or adhered part or outer surface of the resultant structure. Forexample, the cementitious foam slurries (preferably further containingmacrofibers, aggregates, sand, stones, and/or other fillers) can bepoured into metal, plastic, or wood molds to form a door or otherbuilding material, such as blocks (e.g., cinder blocks, masonry blocks),bricks, pavers, window or door framing, posts for use in fences, or insound barriers.

Another exemplary application is the use of spraying or pumping of thecementitious foam to achieve an R value of 3.3 or higher. Anotheradvantage over current pumped or sprayed materials is the fact that theinorganic matrix of the cementitious foams provides fire resistancewithout using toxic foaming agents. Moreover, the cementitious foam inits hardened state does not warp at slightly elevated temperatures(around 60 degrees C.) which can be caused by direct sunlight or heatingsources. Thus, useful applications in view of this feature includecavity walls and exterior wall insulation.

Other articles and applications of the cementitious foams of theinvention include sound proofing, either in preformed panels or as apoured underlayment or filling for wall cavities, as decorative shapes(such as house moldings, fence posts, etc.), and siding for houses. Aspreviously mentioned in the summary, exemplary articles of the inventioninclude laminated, coated, or injected assemblies, such aspre-waterproofed exterior wall boards or roof decking (e.g., havingpre-attached or pre-adhered waterproofing membrane), vinyl-cladclapboards for house exteriors, or as foam core in steel doors.

Exemplary very low density cementitious foams and three-dimensionalstructures (articles) may have, for example, specific gravity under 0.1g/cm³ and insulation (k) value under 0.045 W/(m ° K), and this isbelieved to be suitable for use as insulation material, such as for usein walls.

Exemplary low density cementitious foams and structures of the inventionmay have a specific gravity between 0.1-0.35 g/cm³ and an insulation (k)value under 0.05 W/(m ° K), and this is believed to be suitable forspray, pumping, pouring, or trowel applications, particularly where oneside might be exposed to the air.

Exemplary medium density cementitious foams and structures of theinvention may have a specific gravity between 0.35-0.45 g/cm³ and aninsulation (k) value under 0.05 W/(m° K), and this is believed to besuitable for insulating concrete for use on roofs and cavities, with orwithout reinforcing meshes, waterproofing membranes (e.g.,underlayments), can be used to replace gypsum boards, autoclave blocks,decorative cementitious objects, sound insulation, or panels (such asmay be used as siding material for houses and buildings).

Further exemplary moderate density cementitious foams and structures ofthe invention may have a specific gravity between 0.45-0.7 g/cm³ and aninsulation (k) value under 0.08 W/(m° K), and these can be used ashigher density material for the applications noted above for mediumdensity foams.

Further exemplary light-weight cementitious foams and structures of theinvention may have a specific gravity between 0.7-1.0 g/cm³ and aninsulation (k) value under 0.1 W/(m° K), and these can be used as higherdensity material for the applications noted above for medium andmoderate density foams, where higher strength and durability are needed.

Finally, light-weight cementitious foams and structures of the inventionmay have a specific gravity between 1.0-1.8 g/cm³ and an insulation (k)value under 0.2 W/(m° K), and these can be used in applications whereinlight-weight concrete is used (e.g., floors, blocks for walls, precastconcrete panels, glass fiber-reinforced concrete).

While the invention is described herein using a limited number ofembodiments, these specific embodiments are not intended to limit thescope of the invention as otherwise described and claimed herein.Modification and variations from the described embodiments exist. Morespecifically, the following examples are given as a specificillustration of embodiments of the claimed invention. It should beunderstood that the invention is not limited to the specific details setforth in the examples. All parts and percentages in the examples, aswell as in the remainder of the specification, are by percentage weightunless otherwise specified.

Further, any range of numbers recited in the specification or claims,such as that representing a particular set of properties, units ofmeasure, conditions, physical states or percentages, is intended toliterally incorporate expressly herein by reference or otherwise, anynumber falling within such range, including any subset of numbers withinany range so recited. For example, whenever a numerical range with alower limit, RL, and an upper limit RU, is disclosed, any number Rfalling within the range is specifically disclosed. In particular, thefollowing numbers R within the range are specifically disclosed: R═RL+k″(RU−RL), where k is a variable ranging from 1% to 100% with a 1%increment, e.g., k is 1%, 2%, 3%, 4%, 5% . . . 50%, 51%, 52% . . . 95%,96%, 97%, 98%, 99%, or 100%. Moreover, any numerical range representedby any two values of R, as calculated above, is also specificallydisclosed.

Example 1

Ten foam compositions were created by preparing a foam generation systemand cementitious slurry system, and mixing them to form cementitiousfoam slurry within a mold (or form), as follows.

The foam generation system comprises polyvinyl alcohol (PVOH); apolycarboxylate (PC) surfactant (e.g., TAMOL™ 731 DP available from Rohm& Haas); a shrinkage reduction admixture (“SRA” such as hexylene glycol,or “HG” for short); calcium nitrite (which is available from GraceConstruction Products, Cambridge, Mass., under the trade name “DCI®)”; aviscosity modifying agent (e.g., methylcellulose); and a plurality ofmicrofibers (which were made of polyethylene, had a mean transversedimension or thickness of about 30-32 um (microns) and which comprised amixture of polyethylene fibers having average lengths of 1.5 mm and 0.8mm, respectively). To this foam generation system, water is incorporatedand mixed until a self-supporting foam was generated.

The cementitious slurry system comprises a borate (e.g., bariummetaborate), an optional polycarboxylate (PC) surfactant (e.g., TAMOL™731 DP), a cement (which is optionally white for aesthetic effect), andan expansion agent (e.g., calcium sulfoaluminate, available from Denka).Optional cementitious slurry components were also evaluated: includingcolloidal cement, which has a very fine average particle size (availablefrom Denka K. K. under the trade name “Super Cement” which has averageparticle size of under 1 mm); an SRA (e.g., hexylene glycol, or “HG”);and polypropylene reinforcing fibers. For testing purposes, twodifferent sizes of polypropylene (PP) fibers were used, a first batch ofPP fibers having an average length of 8 mm, with average equivalentdiameter of 5-32 microns; and a second batch of PP fibers having anaverage length of 5 mm, with average equivalent diameter of 5-32microns. To this cementitious slurry system, water is incorporated andmixed until relatively uniform slurry was generated.

The amount of each component, indicated as a percentage based on totalweight of the cementitious foam compositions, is presented in Table 1.

TABLE 1 SAMPLE: P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 % % % % % % % % % %Foaming Component PVOH 4.00 4.00 4.00 3.94 3.91 4.00 3.94 3.91 3.94 3.88PC Surfactant 0.64 0.64 0.64 0.63 0.63 0.64 0.63 0.63 0.63 0.62 SRA (HG)1.92 1.25 1.92 1.25 2.17 Calcium Nitrite 4.83 4.83 4.80 4.73 4.70 4.804.73 4.70 4.72 4.65 VMA 0.06 0.06 Microfibers 0.16 0.16 0.16 0.16 0.160.16 1.5 mm PE Microfibers 0.09 0.09 0.09 0.09 0.16 0.16 0.8 mm PE Water45.09 45.09 43.52 44.12 44.12 43.52 44.12 43.22 44.09 42.79 CementitiousSlurry Borate 0.64 0.64 0.64 0.64 0.64 0.64 0.64 0.64 0.63 0.62 PCSurfactant 0.32 0.32 0.32 0.32 0.31 0.32 0.32 0.31 0.31 0.31 SRA (HG)0.95 0.94 0.95 0.94 0.94 0.93 Microfibers 0.47 0.47 0.47 0.47 0.47 0.478 mm PP Microfibers 0.47 0.47 0.47 0.47 0.47 0.47 5 mm PP Water 12.2412.24 12.16 11.98 11.90 12.16 11.98 11.90 11.97 11.78 Cement 16.10 32.2132.00 31.52 31.32 16.00 15.76 15.66 15.75 15.50 Colloidal Cement 8.058.00 7.88 7.83 7.87 7.75 CSA (expansion) 8.05 8.00 7.88 7.83 7.87 7.75Total 1.879 1.879 1.899 1.879 1.899 1.899 1.879 1.899 1.879 1.929Water/Cement Initial Wet 0.099 0.103 0.089 0.100 0.100 0.070 0.094 0.1110.107 0.121 Density (g/cm³) Final Dry Density 0.047 0.047 0.046 0.0500.050 0.030 0.045 0.056 0.057 0.070 (g/cm³) Comp. Strength 0.028 0.0310.010 0.060 0.072 0.023 0.119 0.208 0.158 0.283 dry (MPa) Strength-to-0.60 0.66 0.22 0.21 0.146 0.76 2.63 3.73 2.78 4.06 Density (metric)

Each of samples P1 through P10 were cast into expanded polystyreneframed molds and allowed to air dry and the photographs of these samplesare shown in FIG. 1.

The foregoing data supports the conclusion that addition of an expansiveagent (CSA) or shrinkage reducing agent (HG) alone is not enough toprevent excessive shrinkage, as demonstrated by gaps at the form walls,cracking and a reduction in volume for samples P1 through P9.

It also supports the conclusion that microfibers fibers help withprevention of cracking, but do not eliminate excessive shrinkage. SampleP10 of this invention had the best dimensional stability as well as thehighest strength-to-density ratio.

The data supports the conclusion that the calcium nitrite componentimproved the workability of the material by preventing the earlycross-linking of the PVOH component. An added benefit is conferred bythe ability of calcium nitrite to offset cement retardation due to thepresence of the borate component.

Example 2

From Example 1, it was determined that the use of a viscosity modifyingagent such as methyl cellulose provided benefits, in combination withthe expansion agent (CSA), in terms of enhanced strength-to-densityratio (metric). Sample “P9” contained methyl cellulose, expansion agent,and microfibers. Sample “P10” of the present invention further containedshrinkage reducing admixture (SRA), e.g., hexylene glycol (“HG”), whichincreased strength-to-density from 2.78 for P9 to 4.06 for P10.

FIG. 2 contains a photograph of the sample P10 containingmethylcellulose, expansive agent, and shrinkage reduction agent (leftside) compared to another sample which contained only methylcelluloseand expansion agent but without shrinkage reduction agent (right side).

Further testing was done to ascertain the effect of removing the SRA andall fiber components (Sample “P11”), decreasing the relative amount ofSRA but retaining the fiber components (Sample P12), and removing thecalcium nitrite component (Sample P13).

The results are shown in Table 2 below.

TABLE 2 P11 P12 P13 % % % Foaming Component PC Surfactant 0.64 0.63 0.64Foam Stabilizer (PVOH) 4.02 3.94 4.00 SRA (HG) 0.32 Calcium Nitrite 4.834.72 VMA (methyl cellulose) 0.06 0.06 0.06 Microfibers 1.5 mm PE 0.160.16 Microfibers 0.8 mm PE 0.09 0.09 Water 45.09 43.78 47.68Cementitious Slurry Borate 0.64 0.63 0.64 PC Surfactant 0.32 0.31 0.32SRA (HG) 0.94 0.96 Microfibers 8 mm PP 0.47 0.47 Microfibers 5 mm PP0.47 0.47 Water 12.23 11.97 12.26 Cement 16.09 15.75 16.00 DenkaColloidal 8.05 7.87 8.00 Expansion (Denka CSA) 8.05 7.76 8.00 TotalWater/Cement 1.879 1.879 1.879 Initial Wet Density (g/cm³) 0.11 0.130.18 Final Dry Density (g/cm³) 0.05 0.06 0.08 Comp Strength dry (MPa)0.09 0.20 0.28 Strength-to-Density Ratio 1.65 3.32 3.73

Example 3

Eliminating calcium nitrite increased density, as shown by Sample P13 inTable 2 above. It was also observed that workability of the P13 samplemixture and pot life was reduced. This behavior appears consistent withthe fact that the calcium nitrite acts as a retarder for cross-linkingPVOH.

This result is illustrated in FIG. 3, which is a set of side-by-sidecomparative photographs of air dried cementitious foam sample P10 (leftphoto) which contained calcium nitrite, and sample 13 that did notcontain calcium nitrite (right photo). The right photo of the calciumnitrite-free sample demonstrated that shrinkage was still controlled (novisible pulling away from wooden form), so this formulation could beused if the material is placed quickly after mixing. However, asmentioned above, the density was higher than sample P10 on left.

Example 4

The thermal conductivity (k) of various sample cementitious foamcompositions made in accordance with the invention, as a function ofdensity, is provided in Table 3 below, and plotted against values ofcommercial materials in FIG. 4.

TABLE 3 Density (g/cm³) W/(m° K) Sample Numbers P14 0.0671 0.0345 P140.0671 0.0373 P14 0.0673 0.0404 P15 0.1463 0.0425 P15 + P16 0.17680.0424 P16 0.2066 0.0416 P17 0.5466 0.0533 P18 0.1109 0.036 P19 0.11620.0377 P21 0.6742 0.0655 P20 0.2772 0.0432 P26 0.0764 0.0401 P31 0.07280.0352 P31 0.0728 0.0401 P31 0.0707 0.0405 P23 0.2104 0.041 P26 0.05930.0412 P26 0.0641 0.039 P30 0.1830 0.0374 P30 0.1841 0.036 P30 0.21470.0461 P34 1.8968 0.1862 PRIOR ART SAMPLES BELOW Light Weight Concrete(LWC) 0.3205 0.1008 Insulating LWC 0.4808 0.1442 Insulating LWC 0.64100.1737 Insulating LWC 0.9615 0.2773 Structural LWC 1.4423 0.4807Structural LWC 1.7628 0.7591 Structural LWC 1.9231 1.0302 Normal WeightConcrete 2.4038 2.2189 Typical Gypsum Board 0.7692 0.1601 GeorgiaPacific 0.8814 0.1254 Dens Glass Gold ® Zonolite ® Insulating Concrete0.4006 0.0968 for Roof Deck Insulcel ® Insulating Concrete 0.5288 0.1109for Roof Deck Zonocel ® Insulating Concrete 0.5288 0.1311 for Roof DeckInsulperm Insulating XPS 0.0160 0.03605 Board(component of Siplastroofing systems) Note that Sample P17 used PVOH having 87.5-89%hydrolyzed.

FIG. 4 is a graph plot of density (horizontal axis) against K-value(vertical axis) of published values for commercial inorganic insulationmaterials, which included lightweight cement-based insulating material,a so-called “light weight” concrete, gypsum board, and lightweightinsulating concrete (available from SIPLAST Corporation).

In contrast, it will be seen that cementitious foam materials of thepresent invention will have lower k values than commercially availableinorganic materials at the same density levels.

In addition, the k values at densities between approximately 0.05 and0.25 g/cm3 are close to each other even though there is a significantincrease in density. This occurs because unlike other systems, thecementitious foams of the present invention have closed-cell structuresat a relatively low density of about 0.19 g/cm3, as shown by the sharpdrop off in air permeability in FIG. 5, and the micrograph FIG. 6.

FIG. 5 is a graph plot of density (g/cm³) along the horizontal axisagainst air permeability, in terms of liters of air per second persquare meter (at 74 Pascals of pressure, with a correction factor asshown on the graph) to convert to air permeability as a function ofsurface area per square meter per second) along the vertical axis ofcommercially available insulation, plywood sheeting, and gypsum board.

FIG. 6 is a set of microphotographs of an exemplary light weightcementitious foam composition of the present invention. As shown in the,right photo, the closed cell bubbles are significantly less than one mm(as indicated by the markings which are spaced 1 mm apart). As shown inthe left photo, taken at a higher magnification, the closed cell bubblesare highly distinct and separated, with the matrix of material betweenthe closed pores being minimal, and suggested the ability of the presentinvention to achieve high porosity and thus low density with the abilityto obtain high insulative values and strength due to the closedstructure.

Exemplary cementitious foams, articles, and structures of the inventionwill have closed cell air void bubbles that are on the average less than200 microns diameter.

The lower density materials have the advantage of having more air andthus a lower cost, where air impermeability is not needed, and as shownin Example 1 have much higher strength than inorganic foams made withoutusing the teachings of this invention.

Example 5

Three cementitious foam slurry samples were made using water/cement(W/C) ratios of 1.9, 1.31, and 1.21, respectively, for sample numbersP14, P16, and P17. The foaming component was made using a foamstabilizer (PVOH), a PC Surfactant (TAMOL™ 731 DP), an SRA (hexyleneglycol or “HG”), a water repellent (e.g., disodium succinate availablefrom Hycrete Technologies, LLC, New Jersey, under the trade name HYCRETEDSS, and, alternatively, fatty acids combined with SRA), calcium nitrite(e.g., available from Grace Construction Products under the trade nameDCI®), a viscosity modifying agent (e.g., methyl cellulose), microfibersof different lengths (e.g., 1.5 and 0.8 mm), fine particulates, andwater. The cementitious slurry component was made using a borate, a PCSurfactant (TAMOL™ 731 DP), an SRA (e.g., HG), microfibers, macrofibers(commercially available from Grace Construction Products under the tradename STRUX®), water, and various cements, as summarized below in Table4A.

TABLE 4A Mix # P-25 Hycrete P-26 P14 P16 P17 DSS/ HG/ 1.9 1.31 1.21Macro Fatty W/C W/C W/C Fibers Acids Foaming Component 53.99% 43.19%40.87% 52.99% 58.24% PVOH 3.91% 3.82% 3.99% 3.55% PVOH (87.5-98% 3.52%hydrolyzed) PC Surfactant 0.63% 0.78% 0.81% 0.64% 0.71% (TAMOL ™ 731 DP)SRA (HG) 1.25% 1.55% 1.62% 1.28% Water Repellant 1.44% 75% HG/25% Fatty1.14% Acids Calcium Nitrite 4.69% 5.81% 6.06% 4.79% 4.26% VMA (MethylCellulose) 0.06% 0.08% 0.08% 0.05% 0.06% Microfibers 1.5 mm PE 0.16%0.19% 0.20% 0.16% 0.14% Microfibers 0.8 mm PE 0.10% 0.13% 0.13% 0.11%0.09% Fine Particulate 3.31% Water 43.19% 30.83% 28.45% 40.53% 44.98%Cement Slurry 46.00% 56.81% 59.14% 47.03% 41.75% Component BariumMetaborate 0.63% 0.61% 0.57% 0.64% 0.57% PC Surfactant 0.31% 0.39% 0.40%0.32% 0.28% (TAMOL ™ 731 DP) SRA (HG) 0.94% 1.16% 1.21% 0.64% 0.85%Microfibers 8 mm PP 0.47% 0.58% 0.61% 0.37% 0.43% Microfibers 5 mm PP0.47% 0.58% 0.61% 0.27% 0.43% Macrofibers 1.06% (Strux ® 85/50) Water11.89% 14.73% 15.35% 11.81% 10.79% White cement 15.65% 19.38% 20.19%15.96% 14.20% Denka Colloidal 7.82% 9.69% 10.10% 7.98% 7.10% supercement Denka CSA 7.82% 9.69% 10.10% 7.98% 7.10% Cement Slurry -to-Foam0.85 1.32 1.45 0.89 0.72 Component by Mass Total W/C (water/ 1.899 1.3141.223 1.899 1.846 cement) Final Dry Density 0.105 0.212 0.694 0.0960.077 (g/cm³) Final Dry Density 0.052 0.125 0.431 0.052 0.047 (g/cm³)Comp. Strength dry 0.114 0.742 2.579 0.080 0.079 (MPa)Strength-to-density 2.18 5.95 5.99 1.55 1.67 Ratio(metric)

The vapor transmission of the cementitious foam slurries, as a functionof density and thickness, was measured (ASTM E 96—wet method) and givenin Table 4B.

TABLE 4B Density Thickness Permeance (g/cm³) (cm) (perms) Mix DesignsP14 First sample 0.059 5.08 cm 1.92 P14 Second sample 0.059 5.08 1.7 P25First sample 0.055 5.08 1.96 P25 Second Sample 0.055 5.08 1.78 P16 Firstsample 0.130 5.08 1.68 P16 Second Sample 0.130 5.08 1.7 P17 First sample0.361 5.08 0.82 P17 Second Sample 0.361 5.08 0.83 P14 4″ Base 0.06010.16 cm 1.07 P25 4″ Hycrete 0.056 10.16  0.94 P26 First Sample 0.0435.08 1.8656 P26 Second Sample 0.043 5.08 1.79 Competitor Regular GypsumBoard 0.769 5.08 6.75 Dens Glass Gold ® Board 0.881 5.08 5.75 Exp.Polystyrene Rigid Board 0.029 5.08 0.23 ccSPF 0.032 5.08 0.95

Even at low densities, the material having 5 cm thickness is able tomeet the criterion for low vapor permeance (less than 2 perms).

FIG. 7 provides a graphic illustration of this data and shows values foranother inorganic material (gypsum board), closed cell polyurethane, andexpanded polystyrene tested in accordance with ASTM E 96. Densities ofthe materials are plotted against permeance values.

Example 6

One potential use of this material is as an insulating material inroofing applications. Table 5 summarizes strength and k values formaterial of this invention in comparison to a commercial cementitiousroofing insulation product that was made with expanded vermiculiteaggregate. At similar strengths and densities the material of thisinvention has a k value that is reduced by at least a factor of 1.5 to2.

TABLE 5 Roof Deck Cementitious Insulation System P37 Foaming Component44.38% PVOH 2.76% PC Surfactant (TAMOL ™ 731 DP) 0.50% SRA/Fatty Acids(75% HG/25% Fatty Acids) 0.88% Calcium salt (calcium nitrite) 3.30% VMA(Methyl Cellulose) 0.05% Microfibers 1.5 mm PE 0.10% Microfibers .8 mmPE 0.06% Fine Particulates 1.77% Water 34.97% Cement Slurry Component55.66% Barium Metaborate 0.35% PC Surfactant (TAMOL ™ 731 DP) 0.38% SRA(HG) 0.94% Microfibers 5 mm PP 0.94% Water 14.61% White Cement 28.83%Expansion Agent (Denka CSA) 9.61% Cement Slurry -to-Foam Component byMass 1.25 Total W/C (water/cement) ratio 1.31 Initial Wet Density(g/cm³) 0.606 Final Dry Density (g/cm³) 0.377 Compressive Strength dry(MPa) 1.014 Strength-to-density Ratio(metric) 2.69 Measured K-Value(W/m° K) 0.0501

FIG. 8 is a set of photographs illustrating sample cementitious foam P37of the present invention (left photo) and its use with a corrugatedsteel deck (right photo). The backside shown in the right photodemonstrates sealing of the gaps between the form and the deckingmaterial; this would eliminate the need to seal against excess loss ofthe material through the cracks.

Example 7

The materials in this invention can be incorporated into boards that canhave a mesh, membrane, or metallic foil on one or both sides (or themesh can be located internally inside the board foam matrix).Cementitious foam composition sample (P35), as summarized in Table 6,was cast against aluminum foil, and another foam composition sample(P35), from Table 6 was cast against a polymeric mesh.

TABLE 6 Sheathing Panel P35 Foaming Component 42.41% PC Surfactant(TAMOL ™ 731 DP) 0.51% PVOH 2.84% 75% HG/25% Fatty Acids 0.91% CalciumSalt (calcium nitrite) 3.40% VMA (Methyl Cellulose) 0.05% Microfibers1.5 mm PE 0.10% Microfibers 0.8 mm PE 0.06% Fine Particulates 1.82%Water 32.72% Cement Slurry Component 57.59% Barium Metaborate 0.36% PCSurfactant (TAMOL ™ 731 DP) 0.40% SRA (HG) 0.97% Microfibers 5 mm PP0.97% Water 15.12% White Cement 29.83% Type I-II Grey Cement ExpansionAgent (Denka CSA) 9.94% Cement Slurry -to-Foam Component by Mass 1.36Total W/C (water/cement) ratio 1.22 Initial Wet Density (g/cm³) 0.769Final Dry Density (g/cm³) 0.481

FIG. 9 contains two photographs demonstrating good adhesion ofcementitious sample P35 cast against aluminum foil, as shown in the leftphoto. As shown in the right photo, the aluminum was not corroded by theeffect of high pH, and this lack of corrosion was due to the use ofcalcium nitrite (a corrosion inhibitor) in the sample formulation P35.

FIG. 10 is a set of four photographs of panels that have been eitherattached or poured against steel studs. The lower left photo depicts a(PRIOR ART) commercial gypsum dry wall product (commercially availableunder the trade name Dens Glass Gold®) fastened against a frame usingstandard fasteners (e.g., screws). The arrow in the lower left photopoints to the collapse the gypsum matrix due to the effect of thefastener. The upper left and lower right photos depict exemplarycementitious foam boards P35 of the present invention which were castinto board shape and then fastened to a steel stud wall using standardfasteners (screws). The arrow in the lower right photo points to thecement matrix surrounding the fastener and shows that this surroundingarea was not damaged due to the effect of the fastener. The upper rightphoto depicts an exemplary cementitious foam sample P36 of the presentinvention that was poured to fill a steel stud.

To decrease drying times, these materials were dried at 60 degreesCelsius, a temperature that was significantly higher than those at whichtypical organic foams are dimensionally stable. This temperature isbelow that typically used in autoclaving of cellular concretes. Dryingtemperatures above 130 degrees Celsius were shown to work.

Example 8

Table 7 gives the composition of a mixture in which all the ingredientswere mixed moved through a pump and pressurized with air as described inU.S. Pat. No. 6,780,230 B2. Solidification times were decreased bymixing barium borate into the spray. The initial wet densities, beforeand after the borate addition, as well as the dry density of the sprayedmixtures, are provided in Table 7.

TABLE 7 P33 P32 Sprayed/Sodium Sprayed/ Bicarbonate & Hycrete/ TetraBorate, Sodium Tetra Barium Borate Metaborate Foam Stabilizer (PVOH)4.08% 3.77% PC Surfactant (TAMOL ™ 731 DP) 1.16% 1.35% SRA (HG) 1.56%1.35% Calcium salt (calcium nitrite) 4.72% 4.72% VMA (Methyl Cellulose)0.10% 0.10% Microfibers 1.5 mm PE 0.13% 0.08% Microfibers 0.8 mm PE0.09% 0.08% Water 54.98% 55.52% Sodium Tetraborate (2.5% solution) 0.05%Barium Metaborate (7.5% Solution) 0.13% Sodium Tetraborate/bicarbonate0.13% (2.5%/15% solution) Microfibers 8 mm PP 0.19% Microfibers 5 mm PP0.19% Water Repellent (Hycrete DSS) 0.94% 0.94% White Cement 15.90%15.90% Denka Colloidal super cement 7.95% 7.95% Expansion Agent (DenkaCSA) 7.95% 7.95% Initial Density (g/cm³) 0.221 0.292 Dry Density (g/cm³)0.121 0.181 Depth Sprayed on Wall Cavity (cm) 3.81 11.43

Example 9

A desirable property of foamed insulations used in areas subject tomoisture is to have a reduced water absorption coefficient. Table 8shows that the foam can be made more water repellent by addinghydrophobic admixtures to either the foam component or cement slurrycomponent. It was observed that the fatty acid addition to the foamcomponent enhanced the stability of the foam, and hence this was thepreferred means of addition. A 20% solution of di-sodium salt oftetrapropenyl butandediodic acid could not be added to the foamcomponent because it would react with the calcium nitrite. Theabsorption by volume and average absorption is provided in Table 8A,while the percentage absorption by mass is provided in Table 8B.

TABLE 8A Absorption Average Density by volume Absorption Mix # .048-.064g/cm³ (g/cm3) (g/cm3) P14 First sample 0.00698 See below P14 Secondsample 0.00862 0.00780 P25 First sample 0.00494 See below P25 Secondsample 0.00545 0.00520 P26 First sample 0.00379 See below P26 Secondsample 0.00333 0.00356

TABLE 8B Mix # Density % Absorption by Mass P14 .052 g/cm³ 8.76% P25.052 g/cm³ 4.77% P26 .047 g/cm³ 5.71%

Example 10

Encapsulation of the liquid components as taught in U.S. Pat. No.6,648,962 B2 allows for some or all the dry components to be premixed,requiring only water to produce the foamed cementitious material. Table9 provides the composition of the dried material as well as wet and drydensities. Cement is introduced in the form of particles which involvehydrating cement with calcium nitrite, allowing particles to dry,crushing the particles, and then coating the crushed particles with acoating comprising an SRA (hexylene glycol) and fatty acid waterrepellents (e.g., combination of oleic acid and stearic acid; or saltform thereof).

TABLE 9 Encapsulated Nitrites/Glycol/Fatty Acids One Component P40Liquid 59.33% Water 59.33% Solid Components 40.69% PC Surfactant(TAMOL ™ 731 DP) 0.51% Foam Stabilizer (PVOH) 3.99% VMA (MethylCellulose) 0.06% Microfibers 1.5 mm PE 0.16% Microfibers 0.8 mm PE 0.10%Barium Metaborate 0.64% PC Surfactant (TAMOL ™ 731 DP) 0.32% SRA (HG)0.96% Microfibers 5 mm PP 0.96% White Cement 16.59% Encapsulated Cement(comprising 13.08% 13.2% Calcium Nitrite in cement, crushed then coatedwith 7.9% SRA (HG) & Fatty Acids (oleic and stearic) Expansive Agent(Denka CSA) 3.19% Solid-to-Liquids by Mass 0.69 Total W/C (water/cement)ratio 1.89 Final Dry Density (g/cm³) 0.212 Final Dry Density (g/cm³)0.115

Example 11

Cementitious foam compositions of the present invention can be combinedwith conventional aggregates to form a lightweight concrete. It isbelieved that the final density of such lightweight concrete will beeasier to control, and the thermal conductivity (k) will be lower thanwhat has typically been reported in the literature. Table 10 gives anexample illustrating this.

TABLE 10 Lightweight Foamed Concrete P34 PC Surfactant (TAMOL ™ 731 DP)0.79% PVOH 0.42% SRA (HG) 1.06% Calcium salt (calcium nitrite) 3.96% VMA(Methyl Cellulose) 0.03% Microfibers 1.5 mm PE 0.13% Microfibers 0.8 mmPE 0.08% Water 12.75% Barium Metaborate 0.07% White Cement 13.19% DenkaColloidal super cement 6.60% Expansive Agent Denka CSA 6.60% ⅜″ CoarseAggregate 34.76% Sand 19.56% Dry Density(g/cm³) 1.82 Measured K-Value(W/m° K) 0.1862

Example 12

While it may be desirable to use white cements for aesthetic reasons,this example demonstrates that cementitious foam compositions of thepresent invention may use grey cement as well. Table 11 illustratesgraphically that the compositions work well with an ordinary gray cement(ASTM C 150 Type 1, 2).

TABLE 11 P38 P39 Samples with Type I-II Grey Cement 25% CSA 10% CSAFoaming Component 57.75% 44.85% PC Surfactant (TAMOL ™ 731 DP) 0.57%0.76% Foam Stabilizer (PVOH) 3.59% 3.33% 75% HG/25% Fatty Acids 0.86%1.39% Calcium nitrite (calcium nitrite) 4.31% 5.74% VMA (MethylCellulose) 0.06% 0.08% Microfibers 1.5 mm PE 0.14% 0.14% Microfibers 0.8mm PE 0.09% 0.09% Fine Particulates 3.59% 2.90% Water 44.54% 30.42%Cement Slurry Component 42.23% 55.14% Barium Metaborate 0.57% 0.54% PCSurfactant (TAMOL ™ 731 DP) 0.29% 0.38% SRA (HG) 0.86% 0.72% Microfibers5 mm PP 0.86% 0.72% Water 10.92% 14.54% Type I-II Grey Cement 21.55%34.42% Expansion Agent (Denka CSA) 7.18% 3.82% Cement Slurry-to-FoamComponent by Mass 0.73 1.23 Total W/C (water/cement) ratio 1.83 1.31Initial wet Density (g/cm³) 0.102 0.212 Final Dry Density (g/cm³) 0.0470.112

Example 13

Polyvinyl alcohol (PVOH) is commercially available at varying levels ofhydrolysis. As shown in Table 12, there can be a significant reductionin water absorption with a more hydrolyzed PVOH. However, a higherdensity cementitious foam product may be obtained by using PVOH withhigher levels of hydrolysis, and this would be more appropriate ifhigher strength and enhanced water resistance are needed.

The system components for two cementitious foam slurry samples areprovided in Table 12A, and the percentage moisture absorption propertiesof these samples are provided in Table 12B.

TABLE 12A P17 P29 (87.5-89% (99% Hydrolyzed Hydrolyzed PVOH) PVOH) 1.21W/C Foaming Component 54.09% 40.87% PC Surfactant (TAMOL ™ 731 DP) 0.62%0.81% Foam Stabilizer (PVOH) 3.52% PVOH 99% Hydrolyzed 3.90% SRA (HG)1.25% 1.62% Calcium salt (calcium nitrite) 4.68% 6.06% VMA (MethylCellulose) 0.31% 0.08% Microfibers 1.5 mm PE 0.16% 0.20% Microfibers 0.8mm PE 0.09% 0.13% Water 43.08% 28.45% Cement Slurry Component 45.90%59.14% Barium Metaborate 0.62% 0.57% PC Surfactant (TAMOL ™ 731 DP)0.31% 0.40% SRA (HG) 0.94% 1.21% Microfibers 8 mm PP 0.47% 0.61%Microfibers 5 mm PP 0.47% 0.61% Water 11.86% 15.35% White Cement 15.61%20.19% Denka Colloidal super cement 7.81% 10.10% Denka CSA (expansion)7.81% 10.10% Cement Slurry-to-Foam Component by Mass 0.85 1.45 Total W/C(water/cement) ratio 1.900 1.223 Initial Wet Density (g/cm³) 0.661 0.694Final Dry Density (g/cm³) 0.403 0.431 Compressive Strength dry (MPa)1.207 2.579 Strength-to-density Ratio(metric) 2.99 5.99

TABLE 12B Mix # % Absorption by Mass P17 .4 g/cm3 Base 7.11% P29 .4g/cm3 99% Hydrolysis PVOH 2.58%

Example 14

Cementitious foam compositions of the present invention can be used withlightweight aggregate additions. An example with expanded polystyreneballs is given in Table 13. Thermal properties were not improved whenadded to the low density foam, but there was an increase in strength.The present inventors suspect that expanded polystyrene can be used invarious forms, such as shredded polystyrene.

TABLE 13 P27 P14 Polystyrene 1.9 Beads W/C Foaming Component 51.41%53.99% PC Surfactant (TAMOL ™ 731 DP) 0.62% 0.63% PVOH 3.87% 3.91% SRA(HG) 1.24% 1.25% Calcium Nitrite 5.16% 4.69% VMA (Methyl Cellulose)0.05% 0.06% Microfibers 1.5 mm PE 0.15% 0.16% Microfibers 0.8 mm PE0.08% 0.10% Water 40.24% 43.19% Cement Slurry Component 48.60% 46.00%Barium Metaborate 0.62% 0.63% PC Surfactant (TAMOL ™ 731 DP) 0.31% 0.31%SRA (HG) 0.31% 0.94% Microfibers 8 mm PP 0.31% 0.47% Microfibers 5 mm PP0.47% Polystyrene Beads 4.64% Water 11.45% 11.89% White Cement 15.48%15.65% Denka Colloidal super cement 7.74% 7.82% Denka CSA (expansionagent) 7.74% 7.82% Cement Slurry -to-Foam Component by Mass 0.95 0.85Total W/C (water/cement) ratio 1.83 1.899 Initial Wet Density (g/cm³)0.107 0.105 Final Dry Density (g/cm³) 0.060 0.052 Compressive Strengthdry (MPa) 0.517 0.114 Strength-to-density Ratio(metric) 8.56 2.18

Example 15

The strength data for the various examples relative to published valuesfor several competitive technologies are shown in FIG. 11, which setsforth the density (along horizontal axis) of these commercial (priorart) materials against their compressive strength (along vertical axis).In contrast, the cementitious foam materials of the present inventionshow an increase in strength-to-density over that found in prior artcompetitive technologies.

Example 16

The effect of calcium chloride on properties was examined and comparedto other calcium salts. U.S. Pat. No. 4,731,389 disclosed the use ofcalcium chloride in Portland cement. Table 14 compares variouscementitious foams.

TABLE 14 P41 No P42 P43 P44 Calcium Calcium Calcium Calcium SaltChloride Nitrate Nitrite Foaming Component 45.7% 46.5% 46.5% 46.5% PVOH3.50% 3.45% 3.45% 3.45% PC Surfactant 0.56% 0.55% 0.55% 0.55% (TAMOL ™731 DP) 75% HG/25% Fatty Acids 0.62% 0.61% 0.61% 0.61% Calcium Chloride1.41% Calcium Nitrite 1.41% Calcium Nitrate 1.41% VMA (Methyl Cellulose)0.05% 0.05% 0.05% 0.05% Microfibers 1.5 mm PE 0.14% 0.14% 0.14% 0.14%Microfibers 0.8 mm PE 0.09% 0.09% 0.09% 0.09% Fine Particulates 1.87%1.84% 1.84% 1.84% Water 38.87% 38.32% 38.32% 38.32% Cement SlurryComponent 54.3% 53.6% 53.6% 53.6% Barium Metaborate 0.56% 0.56% 0.56%0.56% PC Surfactant 0.37% 0.37% 0.37% 0.37% (TAMOL ™ 731 DP) SRA (HG)0.93% 0.93% 0.93% 0.93% Microfibers 5 mm PP 0.93% 0.93% 0.93% 0.93%Water 14.18% 13.98% 13.98% 13.98% White Cement 27.99% 27.59% 27.59%27.59% Denka CSA (expansion agent) 9.33% 9.20% 9.20% 9.20% CementSlurry-to-Foam 1.19 1.15 1.15 1.15 Component by Mass Total Water/Cementratio 1.36 1.36 1.36 1.36 Initial Wet Density (g/cm³) 0.742 0.333 0.2370.186 Final Dry Density (g/cm³) 0.505 0.212 0.144 0.093 Measured K-Value(W/m° K) 0.057 0.039 0.032 0.032 Strength at 10% deformation 2.104 0.5140.129 0.098 (MPa)

Calcium chloride does impart a significant improvement in foam incomparison to foam that does not contain this material. This is evidenceby the lower density and k value for sample P42 which contained calciumchloride in comparison to (control) sample P41 which did not containcalcium chloride. However, the addition of a corrosion inhibitingcalcium nitrite, as shown in sample P43, resulted in a cement samplehaving significantly lower density (56% decrease) and k value incomparison to P41 and P42. This was also true for sample P44, whichcontained calcium nitrate, and which was less corrosive than samplescontaining calcium chloride rather than calcium nitrite. The same kvalue at a higher density for sample P43 compared to sample P44suggested that samples containing calcium nitrite will have higherstrength without sacrificing insulating properties. The samplescontaining the calcium nitrite also foamed more quickly, and thisproperty is seen to be advantageous where speedy application isrequired. The improvements afforded by using nitrite and/or nitrate aresubstantial in comparison to calcium chloride.

Example 17

The effect of adding glycerin to the cementitious foam compositions ofthe invention was examined. Table 15 graphically illustrates thermalproperties of a low density sample (P45) and intermediate densitysamples (P46). These foam samples had slightly lower to comparablethermal properties in comparison to foam samples that did not containglycerin. The present inventors concluded that the optional use ofglycerin imparts flexibility to the foams as they harden over a slightlylonger time. An enhanced skin formed on these examples, and resulted ina smoother surface.

TABLE 15 P47-Sodium P45 P46 Gluconate as 10% 10% Complexing GlycerinGlycerin agent in on PVOH on CaNi cement Foaming Component 45.4% 28.0%45.9% PVOH 3.17% 2.41% 3.40% PC Surfactant 0.51% 0.60% 0.55% (TAMOL ™731 DP) 75% HG/25% Fatty Acids 0.76% 0.54% 0.61% Glycerin 0.32% 0.14%Calcium Nitrite (Grace DCI ®) 3.81% 4.03% 4.08% VMA Methyl Cellulose0.04% 0.05% 0.05% Microfibers 1.5 mm PE 0.13% 0.11% 0.12% Microfibers0.8 mm PE 0.08% 0.05% 0.07% Fine Particulates 1.59% 1.49% 1.82% Water35.03% 18.57% 35.22% Cement Slurry Component 54.6% 72.0% 54.1% BariumMetaborate 0.51% 0.40% 0.55% Sodium Gluconate 0.02% PC Surfactant 0.51%0.40% 0.36% (TAMOL ™ 731 DP) SRA (HG) 1.14% 0.99% 0.91% Microfibers 5 mmPP 1.14% 0.99% 0.91% Water 13.20% 19.07% 14.89% Type I Grey Cement27.33% White Cement 28.56% 37.62% Denka CSA (expansion agent) 9.52%12.53% 9.11% Cement Slurry-to-Foam 1.20 2.57 1.18 Component by MassTotal W/C (water/cement) ratio 1.3 0.79 1.39 Initial Wet Density (g/cm³)0.245 0.646 0.417 Final Dry Density (g/cm³) 0.160 0.540 0.261 MeasuredK-Value (W/m° K) 0.035 0.059 0.040

Example 18

The P47 formulation in Table 15 shows that sodium gluconate can be usedas a retarder in the cementitious slurry component for greaterworkability time in hot weather, without adverse properties on the foamformation. In this example gray cement was used to demonstrate thatwhite cement does not have to be used if appearance is unimportant.

Thus, exemplary cementitious slurry components of the invention mayfurther comprise a gluconate which is operative to retard the cement andthereby confer greater workability.

Example 19

Formulation P48 in Table 16 demonstrates that the amount of methylcellulose can be increased in the foam component. This is advantageousin that it makes it easier to make the foam in a static mixer with air.

TABLE 16 P48 P49 Methyl Low Cost Cellulose Design 35% as VMA onreduction cement slurry in RMC Foaming Component 45.9% 41.8% PVOH 3.40%1.75% PC Surfactant (TAMOL ™ 731 DP) 0.55% 0.44% 75% HG/25% Fatty Acids0.61% 0.66% Calcium Nitrite (Grace DCI ®) 4.08% 2.63% VMA (MethylCellulose) 0.04% Microfibers 1.5 mm PE 0.12% 0.11% Microfibers .8 mm PE0.07% 0.07% Fine Particulates 1.82% Water 35.24% 36.11% Cement SlurryComponent 54.1% 58.2% Barium Metaborate 0.55% 0.22% Methyl Cellulose0.02% PC Surfactant (TAMOL ™ 731 DP) 0.36% 0.22% SRA (HG) 0.91% 0.22%Microfibers 5 mm PP 0.91% 0.66% Water 14.89% 15.32% Type I Grey Cement27.33% 36.11% Denka CSA 9.11% 5.47% Cement Slurry-to-Foam 1.18 1.39Component by Mass Total W/C (water/cement) 1.39 1.29 Initial Wet Density(g/cm³) 0.212 0.194 Final Dry Density (g/cm³) 0.128 0.099 MeasuredK-Value (W/m° K) 0.042 0.042

Example 20

Formulation P49 in Table 16 demonstrates that costs can be lowered forlow density foams by lowering the PVOH content by substituting a portionof the PVOH with an increased amount of methyl cellulose.

Example 21

Foams were produced at low and intermediate densities with either whiteor gray cement to demonstrate that both can be used in cementitious foamslurry systems of the present invention. Table 17 provides graphicillustration of results for samples P50-P53. The gray cement is lesscostly and more readily available for applications where appearance isnot critical, or where darker cement is preferred. Both cementsperformed well.

TABLE 17 P50 P51 P52 P53 Low Low Mid- Mid- Density Density DensityDensity White Grey Grey White Cement Cement Cement Cement FoamingComponent 46.5% 46.5% 28.2% 28.2% PVOH 3.45% 3.45% 2.40% 2.40% PCSurfactant 0.55% 0.55% 0.60% 0.60% (TAMOL ™ 731 DP) 75% HG/25% FattyAcids 0.61% 0.61% 0.87% 0.87% Calcium Nitrite (DCI ®) 4.14% 4.14% 4.02%4.02% VMA (Methyl Cellulose) 0.05% 0.05% 0.06% 0.06% Microfibers 1.5 mmPE 0.14% 0.14% 0.11% 0.11% Microfibers 0.8 mm PE 0.09% 0.09% 0.06% 0.06%Fine Particulates 1.84% 1.84% 1.51% 1.51% Water 35.58% 35.58% 18.54%18.54% Cement Slurry Component 53.6% 53.6% 71.8% 71.8% Barium Metaborate0.56% 0.56% 0.40% 0.40% PC Surfactant 0.37% 0.37% 0.40% 0.40% (TAMOL ™731 DP) SRA (HG) 0.93% 0.93% 1.00% 1.00% Microfibers 5 mm PP 0.93% 0.93%1.00% 1.00% Water 13.98% 13.98% 19.04% 19.04% Grey Cement Type I 27.59%37.49% White Cement 27.59% 37.49% Denka CSA 9.20% 9.20% 12.50% 12.50%Cement Slurry-to-Foam 1.15 1.15 2.55 2.55 Component by Mass Total W/C(water/cement) 1.36 1.36 0.8 0.8 Initial Wet Density (g/cm³) 0.186 0.2150.554 0.562 Final Dry Density (g/cm³) 0.093 0.104 0.439 0.447 MeasuredK-Value (W/m° K) 0.032 0.036 0.052 0.051

Example 22

U.S. Pat. No. 4,731,389 disclosed cement foams that were based on bothPortland cement and magnesium oxide. However, it was observed thatcommercial activity of the assignee of this patent appeared to involveprimarily the magnesium oxide version.

Table 18 shows several attempts at producing a Portland cement versionusing the same processes that were purportedly disclosed in this patent.However, the present inventors discovered that only one of fivevariations worked, and that the material that worked was weaker thancementitious foam compositions taught by the present invention havingsimilar density. Volume stability was not obtained for the sample madein according to the '389 prior patent, because this prior art sampleshrunk to half its initial size. Moreover, the present inventors couldnot obtain consistent results, suggesting a lack of repeatability inthis prior art approach.

TABLE 18 Attempts to make foam slurry according to U.S. Pat. No.4,731,389 attempt attempt attempt attempt attempt 1 2 3 4 5 FoamingComponent 50.2% 50.1% 50.1% 49.6% 49.6% PVOH(11% aqueous 16.74% 23.59%23.59% 23.64% 23.64% solution) Calcium Chloride 2.51% 3.53% 3.53% 3.54%3.54% Precipitated Calcium 2.51% 0.60% 0.60% 0.61% 0.61% Carbonate1,3-butylene glycol 3.35% 4.72% 4.72% 4.04% 4.04% Water 25.10% 17.69%17.69% 17.73% 17.73% Cement Slurry 49.8% 49.9% 49.9% 50.4% 50.4%Component Portland Cement Type I 25.10% 21.87% 21.87% 21.92% 21.92%Precipitated Calcium 1.67% 1.41% 1.41% 1.41% 1.41% Carbonate SodiumMetaborate 2.51% 2.82% 2.82% (8 mol) Barium Metaborate 3.28% 3.28%Glyoxal 1.67% 1.90% 1.90% 1.90% 1.90% e-Caprolactam 0.84% 0.95% 0.95%0.95% 0.95% Indopol L-14 polybutene 0.84% 0.95% 0.95% 0.95% 0.95%polymer NORLIG ™ 41N 0.42% 0.95% 0.95% 0.95% 0.95% Water 16.74% 19.01%19.01% 19.06% 19.06% Cement Slurry-to-Foam 0.99 1.00 1.00 1.02 1.02Component by Mass Total W/C (water/ 1.80 1.89 1.89 1.86 1.86 cement)Initial Wet Density 0.160 0.157 (g/cm³) Final Dry Density 0.056 0.067(g/cm³)

Example 23

U.S. Pat. No. 4,731,389 taught the use of 1,3 butylene glycol andIndopol™ L-14. As shown in Example 22, the use of 1,3 butylene glycoldid not work well in providing a stable foam. In this example, thepresent inventors explored drying shrinkage properties using a standardmortar mixture and compared this with samples having Indopol™ L-14 or,as used in the present invention, hexylene glycol.

Table 19 summarizes mixture proportions of the samples.

TABLE 19 1,3- 1,3- Hexylene butylene butylene Standard Mortar MixControl Glycol glycol glycol Type I cement 22.22% 22.22% 22.22% 22.22%Sand 66.67% 66.67% 66.67% 66.67% Water 11.11% 10.67% 10.67% 10.67%Hexylene Glycol 0.44% 1,3-butylene glycol 0.44% Indopol ™ L-14 0.44% W/C(water/cement) 0.50 0.50 0.50 0.50 Air content % 4.60% 5.80% 5.20% 4.20%Unit Weight g/cm³ 2.20 2.17 2.19 2.21

The drying shrinkage results are illustrated in FIG. 12, whichgraphically illustrates in terms of time (along horizontal axis) againstlength-wise shrinkage of a control cement sample, a cement samplecontaining hexylene glycol (HG), and two cement samples containing 1,3butylene glycol and INDOPOL™ L-14.

It was observed that there was essentially no benefit for shrinkagereduction with INDOPOL™ L-14; and the 1,3 butylene glycol is not aseffective as hexylene glycol. As mentioned previously, good shrinkagereduction is needed to have dimensionally stable foam. The presentinventors believe that a shrinkage reducing admixture is needed whichdoes not act as a strong defoamer. Thus, the two materials mentioned inU.S. Pat. No. 4,731,389 are not suitable for Portland cement based foamsas produced with this invention.

Example 24

Additional experiments were conducted to determine if polyvinyl acetate(PVA) would work as well as polyvinyl alcohol (PVOH) in stabilizing thefoam component, and to determine the preferred degree of hydrolysis(PVOH). The PVOH used is commercially available from Celanese under thetrade name CELVOL™. The PVA materials were sourced from Nippon andAirvol. Cementitious foam slurries were made according to theformulations described in Table 20A, and viscosity and hydrolysisproperties are described in Table 20B.

TABLE 20A P56 P54 P55 Nippon P57 Celvol Nippon GM- Nippon P58 523 z-20014R T330-H Airvol PVOH PVA PVA PVA PVOH Foaming Component 42.3% 42.3%42.3% 42.3% 42.3% PVOH (T/S in 5% 1.90% 1.90% solution) PVA (T/S in 5%1.90% 1.90% 1.90% solution) PC Surfactant 0.30% 0.30% 0.30% 0.30% 0.30%(TAMOL ™ 731 DP) SRA (HG) 0.46% 0.46% 0.46% 0.46% 0.46% Calcium Nitrite(DCI) 2.28% 2.28% 2.28% 2.28% 2.28% VMA (Methyl Cellulose) 0.02% 0.02%0.02% 0.02% 0.02% Microfibers 1.5 mm PE 0.07% 0.07% 0.07% 0.07% 0.07%Microfibers 0.8 mm PE 0.05% 0.05% 0.05% 0.05% 0.05% Monterey Limestone1.14% 1.14% 1.14% 1.14% 1.14% Water 36.11% 36.11% 36.11% 36.11% 36.11%Cement Paste 57.7% 57.7% 57.7% 57.7% 57.7% Component Barium Metaborate0.34% 0.34% 0.34% 0.34% 0.34% PC Surfactant 0.30% 0.30% 0.30% 0.30%0.30% (TAMOL ™ 731 DP) SRA (HG) 0.53% 0.53% 0.53% 0.53% 0.53%Microfibers 8 mm PP 0.61% 0.61% 0.61% 0.61% 0.61% Water 15.97% 15.97%15.97% 15.97% 15.97% White Cement 30.41% 30.41% 30.41% 30.41% 30.41%Denka CSA 9.50% 9.50% 9.50% 9.50% 9.50% Cement Paste-to-Foam 1.36 1.361.36 1.36 1.36 Component by Mass Total W/C (water/ 1.31 1.31 1.31 1.311.31 cement) Initial Wet Density 0.245 0.604 0.269 0.945 0.263 (g/cm³)Final Dry Density 0.123 0.502 0.135 0.790 0.136 (g/cm³) Measured K-Value0.032 0.047 0.036 0.055 0.035 (W/m° K)

TABLE 20B Viscosity Hydrolysis Degree (mPA*s) (% mol) P54-Celvol ™523PVOH 23-27 87-89 P55-Nippon ™ z-200 PVA 13.2 99.1 P56-Nippon ™ GM-14RPVA 20 86.5-89  P57-Nippon ™ T330-H PVA 30.2 99.3 P58-Airvol ™ PVOH 9.187-89

The results show that similar densities can be obtained using either PVAor PVOH and that hydrolysis levels below 95% provide cementitious foamshaving more air content. The present inventors therefore determined thatusing PVA or PVOH at 99% hydrolysis was not economical due to loweryield.

The PVA specimens had a smoother more plastic like surface and thusseemed to be more attractive from an aesthetic perspective.

Example 25

Examples up to now achieved higher densities useful for structural orsome fireproofing applications by increasing the ratio of cement tofoam. A more economical means of doing this would be to add aninexpensive cement based filler. One kind of filler could be derivedfrom hydrated cement, of which one source is the filter cake left overfrom aggregate recovery. Another filler that is believed suitable iscrushed concrete. Both of these options would recycle materials that aretypically put into land fills.

In Table 21, the density of the insulating cementitious foam using thesematerials can be increased.

TABLE 21 P59 P60 Crushed Crushed Hydrated 28-day Cement ConcreteAggregate Aggregate Foaming Component 21.81% 23.08% PVOH 540S 1.89%1.85% PC Surfactant (TAMOL ™ 731 DP) 0.47% 0.46% 3:1 SRA(HG):Fatty Acids0.42% 0.42% Calcium Nitrite (DCI) 3.15% 3.09% VMA (Methyl Cellulose)0.04% 0.04% Microfibers 1.5 mm PE 0.08% 0.08% Microfibers 0.8 mm PE0.04% 0.04% Monterey Limestone 1.17% 1.15% Water 14.55% 15.95% CementPaste Component 78.19% 76.90% Barium Metaborate 0.31% 0.31% PCSurfactant (TAMOL ™ 731 DP) 0.31% 0.31% SRA (HG) 0.71% 0.69% Microfibers8 mm PP 0.78% 0.76% Water 14.94% 14.69% Grey Cement 29.47% 28.98% DenkaCSA (expansion agent) 9.82% 9.66% Crushed Hydrated Cement 21.86% CrushedConcrete 21.50% Cement Paste-to-Foam Component by Mass 3.585 3.332 FinalW/C (water/cement) 0.500 0.530 Final Dry Density (g/cm³) 0.87 0.38 WetDensity before Aggregate Addition (g/cm³) 0.73 0.33 Wet Density afterAggregate Addition (g/cm³) 1.13 0.49 Measured K-Value (W/m° K) 0.1430.047 Strength (MPa) 6.95 0.75

Example 26

Table 22A summarizes three mix design samples for making cementitiousfoam having dry density of 0.5 g/cm3. One foam sample is made withoutfibers, a second foam sample is made with microfibers less than 5 mmlong, and a third foam sample is made with macro-sized fibers(commercially available from Grace Construction Products under the brandname STRUX® 90/40) having length of 40 mm, added in addition to themicrofibers.

TABLE 22A Flexural Strength Board Designs P62 P63 (with (without macro-macro- P61 fibers) fibers) Foaming Component 27.84% 27.77% 28.39% PVOH540S 2.40% 2.39% 2.46% PC Surfactant (TAMOL ™ 731 DP) 0.60% 0.60% 0.61%VMA (Methyl Cellulose) 0.06% 0.06% 0.06% Monterey Limestone 1.50% 1.49%1.54% SRA (HG)/Fatty Acids 0.60% 0.60% 0.62% SRA (HG) 0.00% 0.00% 0.00%Calcium Nitrite (DCI) 4.02% 4.01% 4.12% Microfibers 1.5 mm PE 0.11%0.11% Microfibers 0.8 mm PE 0.06% 0.06% Water 18.50% 18.45% 18.98%Cement Slurry Component 71.79% 72.23% 71.61% SRA (HG_coated on PP 5 mmPP 1.00% 1.00% fibers Microfibers 5 mm PP 1.00% 1.00% White Cement37.50% 37.41% 38.47% Denka CSA (expansion agent) 12.50% 12.47% 12.82%Barium Metaborate 0.40% 0.40% 0.41% PC Surfactant (TAMOL ™ 731 DP) 0.40%0.40% 0.41% Macrofibers (STRUX ® 85/50) 0.61% Water 19.00% 18.95% 19.49%Total W/C (water/cement) 0.79 0.79 0.79 Final Dry Density (g/cm³) 0.5110.497 0.501 Ultimate stress at 10% compression 2.280 2.240 2.077 (MPa)Strength-to-density Ratio(metric) 4.46 4.51 4.15

FIG. 13 graphically illustrates toughness performance of cementitiousfoam specimens that are 14 inches long, 4 inches wide by 1 inch thick,tested under third-point loading with the test length of 12 inches. Thegraph is a plot of deflection (horizontal axis) against stress (verticalaxis) of cement samples containing fibers compared to control sample.The results show that there is a significant increase in ductility withthe addition of the fibers with strain hardening and elastic-plasticbehavior. The use of macrofibers significantly increased the peak loadand stiffness of the cementitious foam sample. The specimen withoutfibers broke into two pieces after peak load was reached and was muchmore brittle, but the strain to failure was about 0.5%, which is higherthan the typical 0.06% for ordinary concrete, indicating that the PVOHmight provide some benefits. The improved performance of the sample withfibers is well beyond that of normal concrete. Addition of polypropyleneand polyethylene fibers renders the material less brittle.

Example 27

The addition of a polypropylene mesh significantly improves theperformance of cementitious foam materials made in accordance with thepresent invention.

Data is provided in Table 22B. Several boards 1 inch thick were producedwith mesh or membrane combinations as mentioned in Example 7 withadditional combinations as further described in the present example.

Macrofibers used were commercially available from Grace ConstructionProducts under the trade name STRUX®.

Mechanically fastened and/or fully adhered waterproofing membranes androofing underlayments are commercially available from Grace ConstructionProducts under the trade names TRIFLEX® EXTREME™ and ICE & WATERSHIELD®. Both are believed to be suitable for use in the presentinvention.

TABLE 22B Samples Made 3 samples per with Membrane combination 100Combinations tested on squares Mix Constant Fiber Tinius OlsenWaterproofing per in² Design Loading Macrofibers Membranes mesh P62Fibers: 0.8 mm Strux ® PE, 1.8 mm PE, 85/50 5 mm PP (Grace PP) P62 Sameas above Strux ® Triflex ® 85/50 Extreme (Grace PP) (Grace) P62 Same asabove Strux ® Ice & Water 85/50 Shield ® (Grace PP) (Grace) P62 Same asabove Strux ® Mesh 85/50 (Grace PP) P62 Same as above Strux ® Triflex ®Mesh 85/50 Extreme (Grace PP) (Grace) P62 Same as above Strux ® Ice &Water Mesh 85/50 Shield ® (Grace PP) (Grace) P61 Same as above P61 Sameas above Triflex ® Extreme (Grace) P61 Same as above Ice & Water Shield(Grace) P61 Same as above Mesh P61 Same as above Triflex ® Mesh Extreme(Grace) P61 Same as above Ice & Water Mesh Shield (Grace) P61 Same asabove Mesh on both sides

FIG. 14 graphically illustrates the toughness performance of the fibersamples with and without mesh, compared to a conventional (PRIOR ART)⅝-inch thick gypsum board sold under the trade name Dens Glass Gold® at0.8 g/cm3. The toughness test was run on Tinius Olsen equipment atconstant crosshead speed of 0.635 cm/minute. The results from thisstress/displacement testing show that there is a significant increase instress-resistance when a mesh is used and that elongation issignificantly improved compared to the thinner gypsum board (Dens GlassGold) which would have had even less ductility if it were thicker. Thus,1-inch thick boards made with the cementitious foam material of thepresent invention can be substituted for Dens Glass Gold® board at⅝-inch, giving about a 3 fold increase in R value, an increase inductility by a factor greater than 4, higher flexural strength andtoughness, all at the same weight.

As shown in FIG. 10, cementitious foam structures made in accordancewith the present invention have better resistance to cracking andspalling caused by fasteners.

Example 28

The relative amount of each component of exemplary foaming andcementitious slurry systems will depend on a number of factors,including the desired final density, and also on the mixing equipment.For example, for three cementitious foams having different finaldensities will require adjustments to the individual components, asillustrated in the Table 23, which shows three different sets offoaming/slurry systems. The foam and slurries were made separately bymechanical mixing, and then combined together to form a cementitiousfoam.

TABLE 23 Final Densities (g/cm³) 0.481 0.383 0.192 Foaming System % ofFoam Sol PC Surfactant (TAMOL ™ 731 DP) 1.20% 1.12% 0.99% FoamStabilizer (PVOH) 6.70% 6.21% 5.48% SRA (HG) 2.15% 1.99% 1.75% CalciumSalt (nitrite) 2.73% 2.53% 2.24% VMA 0.12% 0.11% 0.08% Microfibers 1.5mm PE 0.24% 0.22% 0.21% Microfibers .8 mm PE 0.14% 0.13% 0.13% FineParticles 4.29% 3.98% 3.51% Water 82.44% 83.71% 85.61% CementitiousSlurry System % of Slurry Barium Metaborate 0.63% 0.63% 0.63% PCSurfactant (TAMOL ™ 731 DP) 0.69% 0.68% 0.68% SRA (HG used to coatfibers) 1.68% 1.69% 1.69% Microfibers 8 mm PP 1.68% 1.69% 1.69% Water26.25% 26.25% 26.26% Cement 51.80% 51.80% 51.78% Expansive Agent 17.26%17.27% 17.27% Cement Slurry Component addition 1.36 1.25 1.11 by mass toFoam to hit Censity Foaming System % TS of Foam Solution PC Surfactant(TAMOL ™ 731 DP) 6.85% 6.85% 6.90% Foam Stabilizer (PVOH) 38.14% 38.14%38.05% SRA (HG) 12.22% 12.22% 12.19% Calcium Salt (nitrite) 15.53%15.53% 15.53% VMA 0.67% 0.67% 0.59% Microfibers 1.5 mm PE 1.34% 1.34%1.47% Microfibers .8 mm PE 0.81% 0.81% 0.88% Fine Particles 24.44%24.44% 24.39% Part Water To add to Foam Package 4.696 5.139 5.948 CementSlurry Component % TS of Cement Slurry Barium Metaborate 0.85% 0.85%0.85% PC Surfactant (TAMOL ™ 731 DP) 0.94% 0.93% 0.93% HG (coated onMicrofibers) 2.28% 2.29% 2.29% Microfibers 8 mm PP 2.28% 2.29% 2.29%Cement 70.24% 70.23% 70.23% Expansive 23.40% 23.41% 23.42% Part Water Toadd to Cement 0.356 0.356 0.356 Slurry Package

When a static mixer is used, the final density of the cementitious foamwill primarily depend on the equipment settings. Thus, percentageamounts of the various components can vary significantly. Exemplary foamand slurry systems for static mixing are provided in Tables 24 and 25below:

TABLE 24 % of Foam Sol PC Surfactant (TAMOL ™ 731 DP) 1.41% FoamStabilizer (PVOH) 4.93% SRA (HG) 1.24% Water 92.42% % of CementitiousSlurry VMA (Methyl Cellulose) 0.04% SRA (HG)/Fatty Acids 0.00% SRA 0.43%Calcium Salt (nitrite) 2.80% PC Surfactant (TAMOL ™ 731 DP) 0.43%Microfibers 1.5 mm PE 0.22% Microfibers .8 mm PE 0.13% Microfibers 5 mmPP 0.65% White Cement 59.17% Expansion agent (Denka CSA) 10.76% BariumMetaborate 0.86% Water 24.53%

TABLE 25 % TS of Foam Solution Package PC Surfactant (TAMOL ™ 731 DP)18.60% Foam Stabilizer (PVOH) 65.02% SRA (HG) 16.38% % TS ofCementitious Slurry Package VMA (Methyl Cellulose) 0.06% SRA (HG)/FattyAcids 0.00% SRA (HG) 0.57% Calcium Salt (nitrite) 3.71% PC Surfactant(TAMOL ™ 731 DP) 0.57% Microfibers 1.5 mm PE 0.29% Microfibers .8 mm PE0.17% Fibers 5 mm PP 0.86% White Cement 78.39% Expansion Agent (DenkaCSA) 14.25% Barium Metaborate 1.14%

Example 29

Foam was produced using a static mixer, and then pumped into concrete toproduce a lightweight concrete. The concrete used was a high performancemixture having good strength after more than 25% air is added throughinclusion of the foam. Table 26 summarizes details of the mix andvarious hardened properties. The k value of 0.1778 W/(m° K) is over 3times lower than that obtained from a typical lightweight concrete at asimilar density, and similar to that of standard commercial cementitiousmaterials at half the density and lower strength. The present inventorsbelieve that lower foam additions would result in a concrete with aircontent similar to that of air entrained concrete (typically 4.5-8%) ina more controllable process than adding an air entraining admixture.

TABLE 26 P64 Lightweight foam injected concrete Foam Components % FoamMass PC Surfactant (TAMOL ™ 731 DP) 1.54 Foam Stabilizer (PVOH) 5.38 SRA(HG) 1.36 Water 91.7  Air content in foam 86%   Volume Foam Added  14.3L Concrete Mix Before Foam kg/m³ (Based on 1 cu meter of material)Cement 439    Densified Silica Fume (Force 10,000) 36    6-13 mmAggregate 1025     Sand 891    Water 143    Superplasticizer 0.19 SRA(HG) 0.44 Initial Unit Weight 2460 (kg/m³) Volume Concrete Produced28.31 L Wet Unit Weight after Foam added 1538 (kg/m³) Dry Unit Weight offoamed concrete 1500 (kg/m³) Percent Air in Concrete (airpot) 31%  1-day compressive strength (MPa) 2.18 7-day compressive strength (MPa)6.96 K-Value (W/m° K)  0.1775

The foregoing example and embodiments were present for illustrativepurposes only and not intended to limit the scope of the invention.

1. A cementitious foam composition, comprising: (i) a polycarboxylatesurfactant in an amount effective for generating foam in saidcomposition; (ii) a foam stabilizer comprising a polyvinyl alcohol,polyvinyl acetate, or mixture thereof, said foam stabilizer in an amounteffective to stabilize the foam; (iii) a shrinkage reducing admixture inan amount effective to reduce shrinkage in cementitious slurry afterwater is introduced to initiate hydration of cement; (iv) a calcium saltin an amount effective to accelerate setting of cement in cementitiousfoam when water is added to initiate hydration, said calcium saltcomprising calcium nitrite, calcium nitrate, or mixture thereof; (v) aviscosity modifying agent; (vi) a binder comprising Portland cement inan amount effective to provide a cementitious slurry when the cement iscombined with water; (vii) an expansion agent in an amount effective forexpanding by chemical reaction the volume of said cementitious foamcomposition, said expansion agent comprising calcium oxide, magnesiumoxide, calcium sulfoaluminate, or mixture thereof; (viii) across-linking agent in an amount effective for cross-linking said foamstabilizer, said foam stabilizer cross-linking agent comprising aborate, a sulfate, an aluminate, or a mixture thereof; and (ix) aplurality of microfibers in an amount effective to reduce cracking ofthe Portland cement when mixed with water in an amount effective toinitiate hydration of the cement, said microfibers having an effectivediameter of 5-50 microns and comprising cellulose, synthetic polymer,glass, or mixture thereof; and said components (i) through (ix) beingcombined with water in amount effective to form a cementitious foam, toinitiate hydration of said cement binder within the cementitious foam,and to incorporate said components into a foamed cementitious mass,structure, or article upon hardening of the cementitious foam. 2.(canceled)
 3. (canceled)
 4. (canceled)
 5. (canceled)
 6. The compositionof claim 1 wherein said composition is cured into a hardened mass orstructure without the use of autoclave.
 7. (canceled)
 8. (canceled) 9.(canceled)
 10. (canceled)
 11. The composition of claim 1 furthercomprising: (a) lightweight aggregate selected from the group consistingof vermiculite, expanded polystyrene, perlite, and mixtures thereof; (b)a plurality of reinforcing fibers for reinforcing the cement foam; (c) awater repellant agent; (d) particles of supplemental cementitiousmaterial or filler having an average particle size of no greater than 1mm; (e) fine aggregate; (f) coarse aggregate; or (e) mixture of any ofthe foregoing components (a) through (f).
 12. (canceled)
 13. (canceled)14. (canceled)
 15. (canceled)
 16. A composition for making across-linked foamed cementitious product, comprising: (i)polycarboxylate surfactant for generating foam when mixed with water;(ii) a foam stabilizer comprising a polyvinyl alcohol, polyvinylacetate, or mixture thereof; (iii) a shrinkage reducing admixture forreducing shrinkage in a hydrating cementitious composition after wateris added to initiate hydration of said composition; (iv) a calcium saltfor accelerating setting of cement in a cementitious foam when water isadded to initiate hydration, said calcium salt comprising calciumnitrite, calcium nitrate, or mixture thereof; (v) a viscosity modifyingagent; (vi) a binder comprising Portland cement; (vii) an expansionagent for expanding by chemical reaction the volume of the cementitiousfoam composition, said expansion agent comprising calcium oxide,magnesium oxide, calcium sulfoaluminate, or mixture thereof; (viii) across-linking agent for cross-linking said foam stabilizer, said foamstabilizer cross-linking agent comprising a borate, a sulfate, analuminate, or a mixture thereof; and (ix) a plurality of microfibersoperative to reduce cracking of the Portland cement when it is mixedwith water in an amount effective to initiate hydration of the cement,said microfibers having an effective diameter of 5-50 micros andcomprising cellulose, synthetic polymer, glass, or mixture thereof. 17.The composition of claim 16 further comprising water in an amounteffective to initiate hydration of said binders.
 18. (canceled) 19.(canceled)
 20. (canceled)
 21. (canceled)
 22. The composition of claim 16further comprising incorporating fine aggregate, coarse aggregate, ormixture thereof.
 23. (canceled)
 24. (canceled)
 25. The composition claimof 16 wherein said components (i)-(iv) are provided as a separate firstfoam system and components (v)-(ix) are provided as a separatecementitious slurry system.
 26. (canceled)
 27. The composition claim 16further comprising (a) lightweight aggregate selected from the groupconsisting of vermiculite, expanded polystyrene, perlite, and mixturesthereof; (b) a plurality of reinforcing fibers for reinforcing thecement foam; (c) a water repellant agent; (d) particles of supplementalcementitious material or filler having an average particle size of nogreater than 1 mm; (e) sand; (f) coarse aggregate; or (g) mixture of anyof the foregoing components (a) through (f).
 28. (canceled)
 29. Thecomposition of claim 1 being molded or shaped into a three-dimensionalshape.
 30. The composition of claim 1 being sprayed against a surface orsubstrate.
 31. (canceled)
 32. (canceled)
 33. (canceled)
 34. (canceled)35. (canceled)
 36. (canceled)
 37. (canceled)
 38. (canceled) 39.(canceled)
 40. (canceled)
 41. (canceled)
 42. (canceled)
 43. (canceled)44. (canceled)
 45. (canceled)
 46. (canceled)
 47. (canceled) 48.(canceled)
 49. (canceled)
 50. A composition for generating a foamedcementitious material, comprising when combined with a hydratablecementitious slurry: (i) a polycarboxylate surfactant in an amounteffective for generating foam when combined with a hydratablecementitious slurry; (ii) a foam stabilizer comprising a polyvinylalcohol, polyvinyl acetate, or mixture thereof, said foam stabilizer inan amount effective to stabilize the foam; (iii) a shrinkage reducingadmixture in an amount effective to reduce shrinkage in the cementitiousmaterial after water is introduced to initiate hydration of cement; (iv)a calcium salt comprising calcium nitrite, calcium nitrate, or mixturethereof; and (v) optionally a viscosity modifying agent, microfibers forreducing shrinkage in a cementitious composition, or a mixture thereof.51. The composition of claim 50 comprising a plurality of microfibers toreduce cracking in a foamed cementitious material after the cement iscombined with water to initiate hydration of the cement, saidmicrofibers having an effective diameter of 5-50 microns and beingcomprised of cellulose, synthetic polymer, glass, or mixture thereof.52. The composition of claim 50 further comprising an expansion agent.53. The composition of claim 50 further comprising a cross-linking agentfor said foam stabilizer.